2-Propynyl 2,3,4,6-tetra-O-acetyl-α-d-mannopyran­oside

Al-Mughaid, H.; Robertson, K.N.; Werner-Zwanziger, U.; Lumsden, M.D.; Cameron, T.S.; Grindley, T.B.

doi:10.1107/S010827011005225X

organic compounds

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 67| Part 2| February 2011| Pages o60-o63

doi:10.1107/S010827011005225X

2-Propynyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranoside

Hussein Al-Mughaid,^a Katherine N. Robertson,^b Ulrike Werner-Zwanziger,^b Michael D. Lumsden,^b T. Stanley Cameron ^b and T. Bruce Grindley ^b ^*

^aApplied Chemical Sciences, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan, and ^bDepartment of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3
^*Correspondence e-mail: bruce.grindley@dal.ca

(Received 18 November 2010; accepted 13 December 2010; online 7 January 2011)

The 2-propynyl group in the title compound, C₁₇H₂₂O₁₀, adopts an exoanomeric conformation, with the acetylenic group gauche with respect to position C1. Comparison of ¹³C NMR chemical shifts from solution and the solid state suggest that the acetylenic group also adopts a conformation anti to C1 in solution. The pyranose ring adopts a ⁴C₁ conformation. Of the three secondary O-acetyl groups, that on position O4, flanked by two equatorial groups, adopts a syn conformation, in agreement with recent generalizations [González-Outeiriño, Nasser & Anderson (2005 ). J. Org. Chem. 70, 2486–2493]. The acetyl group on position O3 adopts a gauche conformation, also in agreement with the recent generalizations, but that on position O2 adopts a syn conformation, not in agreement with the recent generalizations.

Comment

2-Propenyl groups attached to carbohydrates as aglycones have become important reactive sites for the creation of larger carbohydrate-bearing molecules via many of the chemistries available to this group, such as click chemistry (van der Peet et al., 2006 ; Balou et al., 2009 ; Müller & Brunsveld, 2009 ; Perez-Balderas et al., 2009 ; Ermeydan et al., 2010 ), Sonagasira coupling (Roy et al., 2000 ; Perez-Balderas & Santoyo-González, 2001 ; Casas-Solvas et al., 2009 ), cyclotrimerization (Kaufman & Sidhu, 1982 ; Dominique et al., 2000 ) and andoxidative coupling (Roy et al., 2001 ; Belghiti et al., 2002 ). Despite this strong interest, particularly directed at 2-propynyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranoside, (I), no structural data are available for any member of this class of compounds. Thus, we present here the structure of (I).

The pyranose ring of (I) adopts a standard slightly distorted ⁴C₁ chair conformation (Fig. 1), with torsion angles ranging from 52.4 (2) to 61.0 (2)° (Table 1). These values resemble those from the cluster of eight α-mannopyranose structures selected from the Cambridge Structural Database (Allen, 2002 ) by Allen & Fortier (1993 ) (σ = 3.2° with the same torsion angles), but are more similar to those of two acylated derivatives, methyl 2,3,4-tri-O-acetyl-α-L-rhamnopyranoside (Shalaby et al., 1994 ) (σ = 2.0° for molecule A and 2.4° for molecule B) and methyl 3,6-di-O-pivaloyl-α-D-mannopyranoside (Matijašić et al., 2003 ) (σ = 2.2°). The ring-puckering parameters (Cremer & Pople, 1975 ) for (I) [Q = 0.573 (2) Å, θ = 5.9 (2)° and φ = 259 (2)°] resemble those of other mannose derivatives (Matijašić et al., 2003). The C—C and saturated C—O bond lengths agree with the values reported for other carbohydrates (Allen et al., 1987 ; Jeffrey, 1990 ; Allen & Fortier, 1993). The C5—C6 rotamer adopted was the gt conformer (Table 1), similar to that observed for methyl 3,6-di-O-pivaloyl-α-D-mannopyranoside (Matijašić et al., 2003), but Allen & Fortier (1993) found that α-mannopyranose derivatives were split 5:3 in favour of the gg over the gt conformer in the solid state.

The C1—O1 bond length is in agreement with previous observations (Allen et al., 1987; Jeffrey, 1990; Shalaby et al., 1994). The aglycone is in the exoanomeric conformation (Lemieux et al., 1979 ), gauche to O5 and anti to C2, as for the other alkyl O-acylated α-mannopyranosides (Shalaby et al., 1994; Matijašić et al., 2003) and indeed for most alkyl α-pyranosides.

Atom C8, the first acetylenic C atom, is gauche to atom C1 [torsion angle = 60.7 (3)°], giving it a syn-1,3 relationship with atom H1. The two alternative staggered positions are the −gauche position, where atom C8 would have a syn-1,3 relationship with atom O5, and the anti position, where atom C8 would have no syn-1,3 relationships. Presumably, a syn-1,3 relationship between an H atom and a linear two-coordinate C atom is not sterically destabilizing. This arrangement of the propargyl group leaves it sterically unencumbered, consistent with its excellent reactivity as mentioned above.

Evidence for the preferences of (I) in solution can be obtained by comparing the solution-state (CDCl₃) ¹³C NMR chemical shifts with those from the solid state (Table 2). Most of the chemical shifts are very similar in the two phases: the standard deviation of the differences between the chemical shifts in the two phases for the four acetyl carbonyl C atoms is 0.92 p.p.m., that for the four acetyl methyl C atoms is 0.74 p.p.m., and that for atoms C2, C3, C5, and C6 is 0.94 p.p.m. Atoms C1 (2.9 p.p.m.), C7 (2.9 p.p.m.), and C4 (2.9 p.p.m.) differ more. The relatively shielded position of atom C1 in the solid state is consistent with the well known γ-gauche shielding effect of its gauche conformation if the solution conformational assembly includes both gauche and anti conformers. The shielded position of atom C7 may arise from differences in the geometry of the gauche and anti conformers, while the effects on atom C4 are probably due to differences in the acetyl group conformations (see below).

The conformations of acetate groups require two torsion angles to be fully described, viz. the H—C—O—C and C—O—C=O torsion angles. The size of the latter is dictated, by resonance within the ester group, to be 0 or 180°, the s-cis or s-trans conformers. Esters strongly prefer the s-cis conformer in the solid state (Leung & Marchessault, 1974 ; González-Outeiriño et al., 2005) and in solution (Grindley, 1982 ), and the four acetate groups of (I) are all in the s-cis conformation. However, all the carbonyl O atoms are disordered to varying extents in directions consistent with libration about the C—O bond. Only one of the acetate methyl C atoms was refined with a two-position disordered model, but the remainder had larger displacement ellipsoids in directions consistent with libration about the carbohydrate-O—carbonyl-C bond. Because the solid-state ¹³C NMR spectrum gives single lines for every C atom, the disorder is fast on the NMR timescale.

González-Outeiriño et al. (2005), based on analyses of structures from the Cambridge Structural Database, have suggested that secondary acetates with two adjacent equatorial substituents will prefer to adopt conformations with H—C—O—C torsion angles close to 0°, i.e. with the C—H bond synperiplanar with the O—C bond. Esters having only one adjacent equatorial substitutent normally adopt conformations with H—C—O—C torsion angles in the range 20–50°. These concepts were originally proposed by Mathieson (1965 ) and elaborated by Schweizer & Dunitz (1982 ). It is thought that the preference arises from the fact that the destabilization accompanying gauche conformations, because of repulsive parallel 1,3 interactions, is larger than that due to the eclipsing interaction of the synperiplanar C—H and O—C bonds (González-Outeiriño et al., 2005).

Compound (I) has three secondary acetate groups providing examples of three of the four possibilities, namely an axial acetate with one flanking equatorial group, an equatorial acetate with one flanking equatorial group and an equatorial acetate with two flanking equatorial groups. The equatorial acetate with two flanking equatorial groups, on atom O4, has an H—C—O—C torsion angle of −4.4°, in agreement with the concepts described above (González-Outeiriño et al., 2005). The equatorial acetate with one flanking equatorial group, on atom O3, has H—C—O—C = 36.1° turned towards atom C2, similar to the 330 cases of this type where the average angle was 27.8° (González-Outeiriño et al., 2005). However, the axial acetate with one flanking equatorial group, on atom O2, has H—C—O—C = −0.5°. This eclipsing arrangement is unusual for this class. González-Outeiriño et al. (2005) indicated that most of the 302 members of the class that they selected from the Cambridge Structural Database were turned away from the equatorial substituent but a substantial minority were not.

The conformations of the acetate groups in solution can be investigated by measuring the size of the ³J_C,H values between the sugar H atoms and the carbonyl C atoms, using the Karplus relationship developed by Andersen and co-workers (González-Outeiriño et al., 2005; Jonsson et al., 2006 ): ³J_C,H = 3.1cos²θ − 1.25cosθ + 2.35. ³J_C,H values were measured using the J-HMBC method of Meissner & Sørensen (2001 ). The chemical shifts and coupling constants observed in the relevant sections of the spectra are given in Table 3. The ³J_C,H values for atoms H2 and H4 were 3.6 Hz, and the value for atom H3 was 3.2 Hz, which yield, from the Karplus equation above, θ values of 30 and 40°, respectively, which are population-weighted averages of the values from the conformations present. For atom H3, the value of 40° is very similar to the X-ray diffraction value (36.4°), as expected. For atom H2, because the acetate was expected to have rotated away from the equatorial group on atom C3, the solution value matches expectation (González-Outeiriño et al., 2005) better than the solid-state value. For atom H4, because an eclipsed conformation was expected, the solution value does not match expectation as well as the X-ray value.

Figure 1
The molecular structure of (I)

, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Only the major components of the disordered acetate groups are shown.

Experimental

To a stirred solution of peracetylated mannose (10.76 g, 0.028 mol) and propargyl alcohol (6.6 ml, 0.11 mol) in dry CH₂Cl₂ (80 ml) was added BF₃ etherate (46.5%, 37.8 ml, 0.14 mol) dropwise at 273 K. The resulting reaction mixture was stirred in the dark for 26 h and then carefully treated with a cold saturated aqueous solution of Na(HCO₃) (200 ml). The organic phase was separated and washed with H₂O (100 ml), dried (MgSO₄) and filtered. The filtrate was then concentrated to a brown residue, which was crystallized from a CH₃OH–EtOAc–hexane mixture (1:1:1 v/v/v) to afford colourless crystals of (I) [yield 7.35 g, 68%; m.p. 375–376 K; literature values 372–378 K (Kaufman & Sidhu, 1982) and 373 K (Roy et al., 2000)]. ¹H and ¹³C NMR data for (I) are similar to those reported previously (Roy et al., 2000).

Crystal data

C₁₇H₂₂O₁₀
M_r = 386.35
Orthorhombic, P 2₁ 2₁ 2₁
a = 9.6848 (5) Å
b = 10.5107 (5) Å
c = 20.1765 (13) Å
V = 2053.8 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 298 K
0.28 × 0.27 × 0.24 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi 1995 ) T_min = 0.708, T_max = 0.979
11076 measured reflections
2396 independent reflections
2255 reflections with I > 2σ(I)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.113
S = 1.06
2396 reflections
284 parameters
4 restraints
H-atom parameters constrained
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

O1—C1	1.399 (3)
O1—C7	1.433 (3)
O2—C2	1.444 (3)
O3—C3	1.444 (3)
O4—C4	1.439 (3)
O5—C1	1.404 (3)
O5—C5	1.436 (3)
O6—C6	1.446 (3)
C1—C2	1.522 (3)
C2—C3	1.516 (3)
C3—C4	1.511 (3)
C4—C5	1.526 (3)
C5—C6	1.509 (3)
C7—C8	1.463 (4)
C8—C9	1.153 (5)

C1—O1—C7	113.41 (17)
C1—O5—C5	113.68 (14)
O5—C1—C2	112.21 (18)
C3—C2—C1	110.30 (17)
C4—C3—C2	109.74 (16)
C3—C4—C5	108.97 (18)
O5—C5—C4	108.74 (16)
O1—C7—C8	112.6 (2)
C9—C8—C7	177.6 (4)

C7—O1—C1—O5	61.2 (2)
C7—O1—C1—C2	−175.8 (2)
C5—O5—C1—O1	61.9 (2)
C5—O5—C1—C2	−57.5 (2)
O1—C1—C2—O2	171.73 (17)
O1—C1—C2—C3	−70.8 (2)
O5—C1—C2—C3	52.4 (2)
O2—C2—C3—O3	−54.7 (2)
O2—C2—C3—C4	63.1 (2)
C1—C2—C3—C4	−53.1 (2)
O3—C3—C4—O4	−64.3 (2)
C2—C3—C4—C5	57.6 (2)
C1—O5—C5—C6	−175.66 (18)
C1—O5—C5—C4	61.0 (2)
C3—C4—C5—O5	−60.2 (2)
C3—C4—C5—C6	−179.45 (17)
O5—C5—C6—O6	−61.9 (2)
C4—C5—C6—O6	58.3 (2)
C1—O1—C7—C8	60.7 (3)
H2—C2—O2—C10	−0.5
H3—C3—O3—C12A	36.1
H4—C4—O4—C14	−4.4
H3—C3—O3—C12B	4.0

Table 2
Comparison of ¹³C NMR chemical shifts from the solid state and in solution in CDCl₃ (p.p.m.)

State	C1	C2	C3	C4	C5	C6	OCH₂	qC	CH
Solid	93.5	70.8†	69.5†	63.3	69.0†	61.1	52.2	79.5	76.7
Solution	96.4	69.5	69.1†	66.2	69.0†	62.4	55.1	78.0	75.7

†Assignments may be interchanged.

Table 3
Solution NMR parameters (CDCl₃)

Position	δ_H (p.p.m.)	³J_H,H+1 (Hz)	δ_C=O (p.p.m.)	³J_H,C=O (Hz)
1	5.01	1.7
2	5.25	3.3	170.03	3.6
3	5.32	10.0	169.92	3.2
4	5.28	9.4	169.78	3.6
5	4.00	2.4, 5.2
6	4.09	²J_H,H 12.2	170.7	3.2
6	4.27			2.5

Some low-angle reflections were eliminated automatically by the software because of streaking and because high local background scatter made their intensities difficult to estimate accurately. All carbonyl O atoms were disordered to varying extents, in directions consistent with libration about the C—O bond. Each acetate O atom was refined with a two-position disordered model. Occupancies for the major components refined to 0.616 (1) for O7, 0.57 (9) for O9 and 0.82 (7) for O10. In addition, one of the complete acetate groups (atoms O8, C12 and C13) had to be refined with a two-position disordered model; the occupancy for the major component refined to 0.910 (6). The C12A/B—O3 bond lengths in the disordered group were restrained to a target value of 1.340 (15) Å and all atoms of the A/B pairs of this disordered group were assigned equal anisotropic displacement parameters. An additional rigid-bond restraint was placed on the C10—O7A bond, and its length was restrained to 1.180 (15) Å. The remaining acetate groups had C atoms with larger displacement ellipsoids in directions consistent with libration, but the disorder was not modelled. All H atoms were placed in geometrically calculated positions and treated as riding, with C—H = 0.96–0.98 Å, and with U_iso(H) = 1.5U_eq(C) for methyl groups and 1.2U_eq(C) otherwise. The H atoms on C11 and C17 were modeled as idealized disordered methyl groups, with the two sets of positions rotated by 60° and occupancies set at 0.5 for each group. The absolute configuration of the structure could not be determined from the X-ray data, since Mo radiation was used and there were no heavy atoms present in the molecule. Friedel opposites were merged in the final refinement. The absolute configuration is known from the starting material used and the product is shown with the known correct configuration.

Data collection: CrystalClear (Rigaku/MSC, 2006 ); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S010827011005225X/gd3372sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S010827011005225X/gd3372Isup2.hkl

Comment top

2-Propenyl groups attached to carbohydrates as aglycones have become important reactive sites for the creation of larger carbohydrate-bearing molecules via many of the chemistries available to this group, such as click chemistry (van der Peet et al., 2006; Balou et al., 2009; Müller & Brunsveld, 2009; Perez-Balderas et al., 2009; Ermeydan et al., 2010), Sonagasira coupling (Roy et al., 2000; Perez-Balderas & Santoyo-González, 2001; Casas-Solvas et al., 2009), cyclotrimerization (Kaufman & Sidhu, 1982; Dominique et al., 2000) and andoxidative coupling (Roy et al., 2001; Belghiti et al., 2002). Despite this strong interest, particularly directed at 2-propynyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranoside (I), no structural data are available for any member of this class of compounds. Thus, we present here the structure of (I)

The pyranose ring of (I) adopts a standard slightly distorted ⁴C₁ chair conformation (Fig. 1), with torsion angles ranging from 52.4 (2) to 61.0 (2)° (Table 1). These values resemble those from the cluster of eight α-mannopyranose structures selected from the Cambridge Structural Database (Allen, 2002) by Allen & Fortier (1993) (σ = 3.2° with the same torsion angles), but are more similar to those of two acylated derivatives, methyl 2,3,4-tri-O-acetyl-α-L-rhamnopyranoside (Shalaby et al., 1994) (σ = 2.0° for molecule A, 2.4° for molecule B) and methyl 3,6-di-O-pivaloyl-α-D-mannopyranoside (Matijašić et al., 2003) (σ = 2.2°). The ring-puckering parameters (Cremer & Pople, 1975) for (I) [Q = 0.573 (2) Å, θ = 5.9 (2)° and ϕ = 259 (2)°] resemble those of other mannose derivatives (Matijašić et al., 2003). The C—C and saturated C—O bond lengths agree with the values reported for other carbohydrates (Allen et al., 1987; Jeffrey, 1990; Allen & Fortier, 1993). The C5—C6 rotamer adopted was the gt conformer (Table 1), similar to that observed for methyl 3,6-di-O-pivaloyl-α-D-mannopyranoside (Matijašić et al., 2003), but Allen & Fortier (1993) found that α-mannopyranose derivatives were split 5:3 in favour of the gg over the gt conformer in the solid state.

The C1—O1 bond length is in agreement with previous observations (Allen et al., 1987; Jeffrey, 1990; Shalaby et al., 1994). The aglycone is in the exoanomeric conformation (Lemieux et al., 1979), gauche to O5 and anti to C2, as for the other alkyl O-acylated-α-mannopyranosides (Shalaby et al., 1994; Matijašić et al., 2003) and indeed for most alkyl α-pyranosides.

Atom C8, the first acetylenic C atom, is gauche to atom C1 [60.7 (3)°], giving it a syn-1,3 relationship with atom H1. The two alternative staggered positions are the –gauche position, where atom C8 would have a syn-1,3 relationship with atom O5, and the anti position, where atom C8 would have no syn-1,3 relationships. Presumably, a syn-1,3 relationship between an H atom and a linear two-coordinate C atom is not sterically destabilizing. This arrangement of the propargyl group leaves it sterically unencumbered, consistent with its excellent reactivity as mentioned above.

Evidence about the preferences of (I) in solution can be obtained by comparing the solution-state (CDCl₃) ¹³C NMR chemical shifts with those from the solid state (Table 2). Most of the chemical shifts are very similar in the two phases: the standard deviation of the differences between the chemical shifts in the two phases for the four acetyl carbonyl C atoms is 0.92 p.p.m., that for the four acetyl methyl C atoms is 0.74 p.p.m., and that for atoms C2, C3, C5, and C6 is 0.94 p.p.m. Atoms C1 (2.9 p.p.m.), C7 (2.9 p.p.m.) and C4 (2.9 p.p.m.) differ more. The relatively shielded position of atom C1 in the solid state is consistent with the well known γ-gauche shielding effect of its gauche conformation if the solution conformational assembly includes both gauche and anti conformers. The shielded position of atom C7 may arise from differences in the geometry of the gauche and anti conformers, while the effects on atom C4 are probably due to differences in the acetyl group conformations (see below).

The conformations of acetates require two torsion angles to be fully described, the H—C—O—C and C—O—C═O torsion angles. The size of the latter torsion angle is dictated by resonance within the ester group to be 0 or 180°, the s-cis or s-trans conformers. Esters strongly prefer the s-cis conformer in the solid state (Leung & Marchessault, 1974; González-Outeiriño et al., 2005) and in solution (Grindley, 1982), and the four acetates of (I) are all in the s-cis conformation. However, all the carbonyl O atoms are disordered to varying extents, in directions consistent with libration about the C—O bond. Only one of the acetate methyl C atoms was refined with a two-position disordered model, but the remainder had larger displacement ellipsoids in directions consistent with libration about the carbohydrate-O—carbonyl-C bond. Because the solid-state ¹³C NMR spectrum gives single lines for every C atom, the disorder is fast on the NMR timescale.

González-Outeiriño et al. (2005), based on analyses of structures from the Cambridge Structural Database, have suggested that secondary acetates with two adjacent equatorial substituents will prefer to adopt conformations with H—C—O—C torsion angles close to zero, i.e. with the C—H bond synperiplanar with the O—C bond. Esters having only one adjacent equatorial substitutent normally adopt conformations with H—C—O—C torsion angles in the range 20–50°. These concepts were originally proposed by Mathieson (1965) and elaborated by Schweizer & Dunitz (1982). It is thought that the preference arises from the fact that the destabilization accompanying gauche conformations because of repulsive parallel 1,3 interactions is larger than that due to the eclipsing interaction of the synperiplanar C—H and O—C bonds (González-Outeiriño et al., 2005).

Compound (I) has three secondary acetates providing examples of three of the four possibilities, namely an axial acetate with one flanking equatorial group, an equatorial acetate with one flanking equatorial group and an equatorial acetate with two flanking equatorial groups. The equatorial acetate with two flanking equatorial groups, on atom O4, has an H—C—O—C torsion angle of -4.4°, in agreement with the concepts described above (González-Outeiriño et al., 2005). The equatorial acetate with one flanking equatorial group, on atom O3, has an H—C—O—C torsion angle of 36.1° turned towards atom C2, similar to the 330 cases of this type where the average angle was 27.8° (González-Outeiriño et al., 2005). However, the axial acetate with one flanking equatorial group, on atom O2, has an H—C—O—C torsion angle of -0.5°. This eclipsing arrangement is unusual for this class. González-Outeiriño et al. (2005) suggested that none of the 302 members of the class that they selected from the Cambridge Structural Database adopted this arrangement.

The conformations of the acetate groups in solution can be investigated by measuring the size of the ³J_C,H values between the sugar H atoms and the carbonyl C atoms, using the Karplus relationship developed by Andersen and co-workers (González-Outeiriño et al., 2005; Jonsson et al., 2006): ³J_C,H = 3.1cos²θ - 1.25cosθ + 2.35. ³J_C,H values were measured using the J-HMBC method of Meissner & Sorensen (2001). The chemical shifts and coupling constants observed in the relevant sections of the spectra are given in Table 3. The ³J_C,H values for atoms H2 and H4 were 3.6 Hz, and the value for atom H3 was 3.2 Hz, which yield, from the Karplus equation above, θ values of 30 and 40°, respectively, which are population-weighted averages of the values from the conformations present. For atom H3, the value of 40° is very similar to the X-ray diffraction value (36.4°), as expected. For atom H2, because the acetate was expected to have rotated away from the equatorial group on atom C3, the solution value matches expectation (González-Outeiriño et al., 2005) better than the solid-state value. For atom H4, because an eclipsed conformation was expected, the solution value does not match expectation as well as the X-ray value.

Related literature top

For related literature, see: Allen (2002); Allen & Fortier (1993); Allen et al. (1987); Balou et al. (2009); Belghiti et al. (2002); Casas-Solvas, Ortiz-Salmeron, Gimenez-Martinez, Garcia-Fuentes, Capitan-Vallvey, Santoyo-González & Vargas-Berenguel (2009); Cremer & Pople (1975); Dominique et al. (2000); Ermeydan et al. (2010); González-Outeiriño, Nasser & Anderson (2005); Grindley (1982); Jeffrey (1990); Jonsson et al. (2006); Kaufman & Sidhu (1982); Lemieux et al. (1979); Leung & Marchessault (1974); Müller & Brunsveld (2009); Mathieson (1965); Matijašić et al. (2003); Meissner & Sorensen (2001); Peet et al. (2006); Perez-Balderas & Santoyo-González (2001); Perez-Balderas, Morales-Sanfrutos, Hernandez-Mateo, Isac-García & Santoyo-González (2009); Roy et al. (2000, 2001); Schweizer & Dunitz (1982); Shalaby et al. (1994).

Experimental top

To a stirred solution of peracetylated mannose (10.76 g, 0.028 mol) and propargyl alcohol (6.6 ml, 0.11 mol) in dry CH₂Cl₂ (80 ml) was added BF₃ etherate (46.5%, 37.8 ml, 0.14 mol) dropwise at 273 K. The resulting reaction mixture was stirred in the dark for 26 h and then carefully treated with a cold saturated aqueous solution of Na(HCO₃) (200 ml). The organic phase was separated and washed with H₂O (100 ml), dried (MgSO₄) and filtered. The filtrate was then concentrated to a brown residue, which was crystallized from a CH₃OH–EtOAc–hexane mixture (1:1:1 v/v) to afford colourless crystals [yield 7.35 g, 68%; m.p. 375–376 K; literature values 372–378 K (Kaufman & Sidhu, 1982); 373 K (Roy et al., 2000)]. ¹H and ¹³C NMR data are similar to those reported previously (Roy et al., 2000).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2006); cell refinement: CrystalClear (Rigaku/MSC, 2006); data reduction: CrystalClear (Rigaku/MSC, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

2-Propynyl 2,3,4,6-tetra-O-acetyl-α-D-mannopyranoside top

Crystal data top

C₁₇H₂₂O₁₀	F(000) = 816
M_r = 386.35	D_x = 1.249 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71070 Å
Hall symbol: P 2ac 2ab	Cell parameters from 5983 reflections
a = 9.6848 (5) Å	θ = 2.9–72.9°
b = 10.5107 (5) Å	µ = 0.10 mm⁻¹
c = 20.1765 (13) Å	T = 298 K
V = 2053.8 (2) Å³	Prism, colourless
Z = 4	0.28 × 0.27 × 0.24 mm

Data collection top

Rigaku R-AXIS RAPID diffractometer	2396 independent reflections
Radiation source: fine-focus sealed tube	2255 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.016
Detector resolution: 10.00 pixels mm^-1	θ_max = 26.5°, θ_min = 2.9°
ω scans	h = −12→9
Absorption correction: multi-scan (ABSCOR; Higashi 1995)	k = −13→9
T_min = 0.708, T_max = 0.979	l = −24→25
11076 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.113	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0724P)² + 0.0949P] where P = (F_o² + 2F_c²)/3
2396 reflections	(Δ/σ)_max < 0.001
284 parameters	Δρ_max = 0.15 e Å⁻³
4 restraints	Δρ_min = −0.13 e Å⁻³

Crystal data top

C₁₇H₂₂O₁₀	V = 2053.8 (2) Å³
M_r = 386.35	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 9.6848 (5) Å	µ = 0.10 mm⁻¹
b = 10.5107 (5) Å	T = 298 K
c = 20.1765 (13) Å	0.28 × 0.27 × 0.24 mm

Data collection top

Rigaku R-AXIS RAPID diffractometer	2396 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi 1995)	2255 reflections with I > 2σ(I)
T_min = 0.708, T_max = 0.979	R_int = 0.016
11076 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	4 restraints
wR(F²) = 0.113	H-atom parameters constrained
S = 1.06	Δρ_max = 0.15 e Å⁻³
2396 reflections	Δρ_min = −0.13 e Å⁻³
284 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
O1	−0.13407 (17)	0.37590 (17)	0.15731 (7)	0.0741 (4)
O2	0.1923 (2)	0.21761 (15)	0.15202 (8)	0.0797 (5)
O3	0.23755 (16)	0.35342 (16)	0.26957 (6)	0.0715 (4)
O4	0.24223 (17)	0.59714 (15)	0.21487 (8)	0.0698 (4)
O5	0.05185 (16)	0.42245 (15)	0.08801 (7)	0.0673 (4)
O6	0.27215 (18)	0.56659 (15)	0.04280 (8)	0.0763 (4)
O7A	0.1740 (6)	0.0541 (5)	0.2215 (4)	0.139 (3)	0.616 (10)
O7B	0.1025 (12)	0.0384 (6)	0.1616 (6)	0.141 (5)	0.384 (10)
O8A	0.0745 (3)	0.2960 (3)	0.34246 (11)	0.0991 (9)	0.910 (6)
O8B	0.084 (3)	0.383 (4)	0.3466 (11)	0.0991 (9)	0.090 (6)
O9A	0.4643 (17)	0.5685 (19)	0.1849 (14)	0.106 (4)	0.57 (9)
O9B	0.4660 (18)	0.5561 (18)	0.204 (3)	0.091 (6)	0.43 (9)
O10A	0.3793 (8)	0.7542 (11)	0.0316 (12)	0.098 (3)	0.82 (7)
O10B	0.384 (3)	0.731 (5)	0.058 (5)	0.098 (9)	0.18 (7)
C1	−0.0141 (2)	0.3299 (2)	0.12698 (11)	0.0680 (5)
H1	−0.0388	0.2577	0.0986	0.082*
C2	0.0776 (2)	0.2822 (2)	0.18294 (11)	0.0675 (5)
H2	0.0264	0.2237	0.2117	0.081*
C3	0.1334 (2)	0.3932 (2)	0.22270 (9)	0.0620 (5)
H3	0.0575	0.4350	0.2463	0.074*
C4	0.2023 (2)	0.48740 (19)	0.17680 (10)	0.0610 (4)
H4	0.2830	0.4489	0.1554	0.073*
C5	0.0979 (2)	0.5312 (2)	0.12499 (10)	0.0648 (5)
H5	0.0186	0.5698	0.1475	0.078*
C6	0.1558 (3)	0.6252 (2)	0.07573 (12)	0.0744 (6)
H6A	0.0857	0.6480	0.0435	0.089*
H6B	0.1851	0.7020	0.0984	0.089*
C7	−0.2372 (3)	0.4169 (3)	0.11105 (14)	0.0841 (6)
H7A	−0.1999	0.4853	0.0842	0.101*
H7B	−0.3158	0.4501	0.1353	0.101*
C8	−0.2837 (3)	0.3141 (3)	0.06754 (13)	0.0898 (7)
C9	−0.3157 (5)	0.2328 (4)	0.03238 (17)	0.1204 (12)
H9	−0.3414	0.1673	0.0040	0.144*
C10	0.2150 (4)	0.0985 (3)	0.1648 (2)	0.1130 (11)
C11	0.3332 (5)	0.0454 (4)	0.1267 (2)	0.1301 (14)
H11A	0.4104	0.1025	0.1296	0.195*	0.50
H11B	0.3071	0.0352	0.0811	0.195*	0.50
H11C	0.3585	−0.0358	0.1449	0.195*	0.50
H11D	0.3070	−0.0345	0.1075	0.195*	0.50
H11E	0.4102	0.0327	0.1560	0.195*	0.50
H11F	0.3588	0.1037	0.0922	0.195*	0.50
C12A	0.1935 (3)	0.3115 (3)	0.32929 (11)	0.0728 (7)	0.910 (6)
C13A	0.3126 (6)	0.2862 (5)	0.3747 (2)	0.1039 (13)	0.910 (6)
H13A	0.2785	0.2648	0.4180	0.156*	0.910 (6)
H13B	0.3693	0.3609	0.3776	0.156*	0.910 (6)
H13C	0.3663	0.2167	0.3577	0.156*	0.910 (6)
C12B	0.203 (4)	0.375 (3)	0.3323 (8)	0.0728 (7)	0.090 (6)
C13B	0.304 (7)	0.340 (6)	0.376 (3)	0.1039 (13)	0.090 (6)
H13D	0.2632	0.3197	0.4181	0.156*	0.090 (6)
H13E	0.3684	0.4087	0.3815	0.156*	0.090 (6)
H13F	0.3522	0.2665	0.3594	0.156*	0.090 (6)
C14	0.3784 (3)	0.6246 (3)	0.21930 (12)	0.0758 (6)
C15	0.3999 (4)	0.7394 (3)	0.26100 (17)	0.1015 (9)
H15A	0.4970	0.7559	0.2651	0.152*
H15B	0.3610	0.7254	0.3041	0.152*
H15C	0.3556	0.8112	0.2406	0.152*
C16	0.3794 (3)	0.6398 (3)	0.02660 (11)	0.0725 (6)
C17	0.4921 (3)	0.5656 (3)	−0.00432 (15)	0.0945 (8)
H17A	0.4676	0.4771	−0.0048	0.142*	0.50
H17B	0.5755	0.5769	0.0207	0.142*	0.50
H17C	0.5063	0.5946	−0.0489	0.142*	0.50
H17D	0.5654	0.6219	−0.0172	0.142*	0.50
H17E	0.4575	0.5221	−0.0427	0.142*	0.50
H17F	0.5266	0.5044	0.0269	0.142*	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0633 (8)	0.0878 (10)	0.0712 (7)	−0.0006 (8)	0.0038 (7)	−0.0087 (8)
O2	0.0907 (11)	0.0596 (8)	0.0889 (9)	0.0141 (8)	0.0156 (9)	0.0046 (7)
O3	0.0679 (8)	0.0856 (10)	0.0610 (7)	0.0073 (8)	0.0073 (6)	0.0117 (7)
O4	0.0651 (8)	0.0637 (8)	0.0806 (8)	0.0022 (7)	0.0101 (7)	−0.0088 (7)
O5	0.0751 (9)	0.0667 (8)	0.0601 (7)	0.0028 (7)	0.0060 (6)	0.0006 (6)
O6	0.0875 (10)	0.0618 (8)	0.0795 (8)	0.0043 (8)	0.0209 (8)	0.0086 (7)
O7A	0.133 (4)	0.092 (3)	0.192 (6)	0.017 (3)	0.027 (4)	0.065 (4)
O7B	0.178 (8)	0.077 (3)	0.167 (9)	−0.050 (4)	0.037 (7)	−0.016 (4)
O8A	0.0951 (14)	0.125 (2)	0.0772 (10)	−0.0262 (15)	0.0167 (10)	0.0165 (13)
O8B	0.0951 (14)	0.125 (2)	0.0772 (10)	−0.0262 (15)	0.0167 (10)	0.0165 (13)
O9A	0.074 (4)	0.139 (9)	0.105 (7)	−0.019 (5)	0.026 (4)	−0.033 (4)
O9B	0.061 (4)	0.084 (6)	0.128 (13)	0.010 (4)	0.016 (6)	−0.023 (6)
O10A	0.110 (2)	0.069 (2)	0.116 (6)	−0.015 (2)	0.026 (3)	0.004 (3)
O10B	0.111 (10)	0.077 (10)	0.11 (2)	−0.037 (10)	0.007 (12)	0.007 (14)
C1	0.0712 (12)	0.0656 (11)	0.0672 (10)	0.0005 (10)	0.0057 (10)	−0.0058 (9)
C2	0.0720 (12)	0.0619 (11)	0.0686 (10)	−0.0016 (10)	0.0110 (10)	0.0067 (9)
C3	0.0603 (9)	0.0666 (11)	0.0590 (9)	0.0059 (9)	0.0088 (8)	0.0046 (8)
C4	0.0622 (10)	0.0574 (9)	0.0635 (9)	0.0041 (8)	0.0089 (9)	0.0007 (8)
C5	0.0685 (11)	0.0584 (10)	0.0676 (10)	0.0101 (9)	0.0083 (9)	0.0024 (8)
C6	0.0829 (14)	0.0620 (11)	0.0783 (12)	0.0125 (11)	0.0116 (11)	0.0126 (10)
C7	0.0734 (13)	0.0866 (15)	0.0922 (14)	0.0072 (13)	−0.0042 (12)	−0.0026 (13)
C8	0.0880 (17)	0.0994 (18)	0.0819 (13)	0.0077 (15)	−0.0188 (13)	−0.0028 (15)
C9	0.128 (3)	0.125 (3)	0.1077 (19)	0.008 (2)	−0.044 (2)	−0.020 (2)
C10	0.103 (2)	0.0585 (13)	0.177 (3)	0.0032 (14)	0.021 (2)	0.0063 (18)
C11	0.126 (3)	0.085 (2)	0.179 (4)	0.038 (2)	−0.008 (3)	−0.032 (2)
C12A	0.0902 (16)	0.0696 (17)	0.0586 (10)	−0.0003 (15)	0.0077 (11)	0.0028 (11)
C13A	0.106 (2)	0.134 (4)	0.0724 (13)	0.029 (3)	0.0011 (15)	0.022 (2)
C12B	0.0902 (16)	0.0696 (17)	0.0586 (10)	−0.0003 (15)	0.0077 (11)	0.0028 (11)
C13B	0.106 (2)	0.134 (4)	0.0724 (13)	0.029 (3)	0.0011 (15)	0.022 (2)
C14	0.0663 (12)	0.0782 (14)	0.0827 (13)	−0.0086 (12)	0.0085 (11)	0.0008 (12)
C15	0.0894 (19)	0.100 (2)	0.1146 (19)	−0.0182 (16)	0.0070 (17)	−0.0236 (17)
C16	0.0775 (13)	0.0783 (14)	0.0618 (10)	−0.0030 (12)	−0.0011 (10)	0.0112 (11)
C17	0.0869 (16)	0.1025 (19)	0.0943 (15)	0.0078 (16)	0.0126 (15)	0.0124 (16)

Geometric parameters (Å, º) top

O1—C1	1.399 (3)	C6—H6A	0.9700
O1—C7	1.433 (3)	C6—H6B	0.9700
O2—C10	1.297 (3)	C7—C8	1.463 (4)
O2—C2	1.444 (3)	C7—H7A	0.9700
O3—C12B	1.326 (14)	C7—H7B	0.9700
O3—C12A	1.352 (3)	C8—C9	1.153 (5)
O3—C3	1.444 (3)	C9—H9	0.9300
O4—C14	1.353 (3)	C10—C11	1.488 (5)
O4—C4	1.439 (3)	C11—H11A	0.9600
O5—C1	1.404 (3)	C11—H11B	0.9600
O5—C5	1.436 (3)	C11—H11C	0.9600
O6—C16	1.334 (3)	C11—H11D	0.9600
O6—C6	1.446 (3)	C11—H11E	0.9600
O7A—C10	1.298 (6)	C11—H11F	0.9600
O7A—O7B	1.403 (11)	C12A—C13A	1.497 (6)
O7B—C10	1.261 (10)	C13A—H13A	0.9600
O8A—C12A	1.193 (4)	C13A—H13B	0.9600
O8B—C12B	1.19 (4)	C13A—H13C	0.9600
O9A—C14	1.234 (14)	C12B—C13B	1.37 (7)
O9B—C14	1.154 (15)	C13B—H13D	0.9600
O10A—O10B	0.58 (8)	C13B—H13E	0.9600
O10A—C16	1.207 (10)	C13B—H13F	0.9600
O10B—C16	1.15 (3)	C14—C15	1.486 (4)
C1—C2	1.522 (3)	C15—H15A	0.9600
C1—H1	0.9800	C15—H15B	0.9600
C2—C3	1.516 (3)	C15—H15C	0.9600
C2—H2	0.9800	C16—C17	1.480 (4)
C3—C4	1.511 (3)	C17—H17A	0.9600
C3—H3	0.9800	C17—H17B	0.9600
C4—C5	1.526 (3)	C17—H17C	0.9600
C4—H4	0.9800	C17—H17D	0.9600
C5—C6	1.509 (3)	C17—H17E	0.9600
C5—H5	0.9800	C17—H17F	0.9600

C1—O1—C7	113.41 (17)	C10—C11—H11E	109.5
C10—O2—C2	119.9 (2)	H11A—C11—H11E	56.3
C12B—O3—C3	113.7 (15)	H11B—C11—H11E	141.1
C12A—O3—C3	117.23 (19)	H11C—C11—H11E	56.3
C14—O4—C4	117.92 (17)	H11D—C11—H11E	109.5
C1—O5—C5	113.68 (14)	C10—C11—H11F	109.5
C16—O6—C6	118.29 (19)	H11A—C11—H11F	56.3
O1—C1—O5	112.57 (18)	H11B—C11—H11F	56.3
O1—C1—C2	105.91 (17)	H11C—C11—H11F	141.1
O5—C1—C2	112.21 (18)	H11D—C11—H11F	109.5
O1—C1—H1	108.7	H11E—C11—H11F	109.5
O5—C1—H1	108.7	O8A—C12A—O3	123.2 (3)
C2—C1—H1	108.7	O8A—C12A—C13A	125.7 (3)
O2—C2—C3	108.43 (19)	O3—C12A—C13A	111.1 (3)
O2—C2—C1	106.49 (17)	C12A—C13A—H13A	109.5
C3—C2—C1	110.30 (17)	C12A—C13A—H13B	109.5
O2—C2—H2	110.5	H13A—C13A—H13B	109.5
C3—C2—H2	110.5	C12A—C13A—H13C	109.5
C1—C2—H2	110.5	H13A—C13A—H13C	109.5
O3—C3—C4	106.42 (17)	H13B—C13A—H13C	109.5
O3—C3—C2	111.88 (17)	O8B—C12B—O3	119 (3)
C4—C3—C2	109.74 (16)	O8B—C12B—C13B	124 (3)
O3—C3—H3	109.6	O3—C12B—C13B	113 (3)
C4—C3—H3	109.6	C12B—C13B—H13D	109.5
C2—C3—H3	109.6	C12B—C13B—H13E	109.5
O4—C4—C3	108.48 (16)	H13D—C13B—H13E	109.5
O4—C4—C5	107.56 (16)	C12B—C13B—H13F	109.5
C3—C4—C5	108.97 (18)	H13D—C13B—H13F	109.5
O4—C4—H4	110.6	H13E—C13B—H13F	109.5
C3—C4—H4	110.6	O9B—C14—O4	124.5 (10)
C5—C4—H4	110.6	O9A—C14—O4	121.2 (9)
O5—C5—C6	107.11 (17)	O9B—C14—C15	123.6 (13)
O5—C5—C4	108.74 (16)	O9A—C14—C15	127.7 (8)
C6—C5—C4	113.7 (2)	O4—C14—C15	110.3 (2)
O5—C5—H5	109.1	C14—C15—H15A	109.5
C6—C5—H5	109.1	C14—C15—H15B	109.5
C4—C5—H5	109.1	H15A—C15—H15B	109.5
O6—C6—C5	108.27 (17)	C14—C15—H15C	109.5
O6—C6—H6A	110.0	H15A—C15—H15C	109.5
C5—C6—H6A	110.0	H15B—C15—H15C	109.5
O6—C6—H6B	110.0	O10B—C16—O6	112 (3)
C5—C6—H6B	110.0	O10A—C16—O6	123.6 (4)
H6A—C6—H6B	108.4	O10B—C16—C17	129.8 (16)
O1—C7—C8	112.6 (2)	O10A—C16—C17	124.2 (5)
O1—C7—H7A	109.1	O6—C16—C17	111.9 (3)
C8—C7—H7A	109.1	C16—C17—H17A	109.5
O1—C7—H7B	109.1	C16—C17—H17B	109.5
C8—C7—H7B	109.1	H17A—C17—H17B	109.5
H7A—C7—H7B	107.8	C16—C17—H17C	109.5
C9—C8—C7	177.6 (4)	H17A—C17—H17C	109.5
C8—C9—H9	180.0	H17B—C17—H17C	109.5
O7B—C10—O2	109.1 (6)	C16—C17—H17D	109.5
O2—C10—O7A	118.1 (4)	H17A—C17—H17D	141.1
O7B—C10—C11	116.8 (5)	H17B—C17—H17D	56.3
O2—C10—C11	112.9 (3)	H17C—C17—H17D	56.3
O7A—C10—C11	123.7 (4)	C16—C17—H17E	109.5
C10—C11—H11A	109.5	H17A—C17—H17E	56.3
C10—C11—H11B	109.5	H17B—C17—H17E	141.1
H11A—C11—H11B	109.5	H17C—C17—H17E	56.3
C10—C11—H11C	109.5	H17D—C17—H17E	109.5
H11A—C11—H11C	109.5	C16—C17—H17F	109.5
H11B—C11—H11C	109.5	H17A—C17—H17F	56.3
C10—C11—H11D	109.5	H17B—C17—H17F	56.3
H11A—C11—H11D	141.1	H17C—C17—H17F	141.1
H11B—C11—H11D	56.3	H17D—C17—H17F	109.5
H11C—C11—H11D	56.3	H17E—C17—H17F	109.5

C7—O1—C1—O5	61.2 (2)	C4—C5—C6—O6	58.3 (2)
C7—O1—C1—C2	−175.8 (2)	C1—O1—C7—C8	60.7 (3)
C5—O5—C1—O1	61.9 (2)	O7A—O7B—C10—O2	−113.1 (5)
C5—O5—C1—C2	−57.5 (2)	O7A—O7B—C10—C11	117.3 (5)
C10—O2—C2—C3	120.7 (3)	C2—O2—C10—O7B	45.9 (7)
C10—O2—C2—C1	−120.6 (3)	C2—O2—C10—O7A	−27.0 (6)
O1—C1—C2—O2	171.73 (17)	C2—O2—C10—C11	177.6 (3)
O5—C1—C2—O2	−65.1 (2)	O7B—O7A—C10—O2	99.9 (7)
O1—C1—C2—C3	−70.8 (2)	O7B—O7A—C10—C11	−107.5 (6)
O5—C1—C2—C3	52.4 (2)	C12B—O3—C12A—O8A	97 (3)
C12B—O3—C3—C4	122.4 (18)	C3—O3—C12A—O8A	6.5 (5)
C12A—O3—C3—C4	154.5 (2)	C12B—O3—C12A—C13A	−84 (3)
C12B—O3—C3—C2	−117.8 (18)	C3—O3—C12A—C13A	−174.3 (3)
C12A—O3—C3—C2	−85.6 (3)	C12A—O3—C12B—O8B	−80 (4)
O2—C2—C3—O3	−54.7 (2)	C3—O3—C12B—O8B	24 (4)
C1—C2—C3—O3	−170.98 (16)	C12A—O3—C12B—C13B	78 (4)
O2—C2—C3—C4	63.1 (2)	C3—O3—C12B—C13B	−178 (4)
C1—C2—C3—C4	−53.1 (2)	C4—O4—C14—O9B	−13 (3)
C14—O4—C4—C3	117.1 (2)	C4—O4—C14—O9A	9.6 (17)
C14—O4—C4—C5	−125.2 (2)	C4—O4—C14—C15	−179.3 (2)
O3—C3—C4—O4	−64.3 (2)	O10A—O10B—C16—O6	−120 (4)
C2—C3—C4—O4	174.47 (17)	O10A—O10B—C16—C17	90 (5)
O3—C3—C4—C5	178.89 (16)	O10B—O10A—C16—O6	75 (4)
C2—C3—C4—C5	57.6 (2)	O10B—O10A—C16—C17	−112 (4)
C1—O5—C5—C6	−175.66 (18)	C6—O6—C16—O10B	22 (5)
C1—O5—C5—C4	61.0 (2)	C6—O6—C16—O10A	−7.9 (14)
O4—C4—C5—O5	−177.61 (15)	C6—O6—C16—C17	177.8 (2)
C3—C4—C5—O5	−60.2 (2)	H2—C2—O2—C10	−0.5
O4—C4—C5—C6	63.1 (2)	H3—C3—O3—C12A	36.1
C3—C4—C5—C6	−179.45 (17)	H4—C4—O4—C14	−4.4
C16—O6—C6—C5	−144.4 (2)	H3—C3—O3—C12B	4.0
O5—C5—C6—O6	−61.9 (2)

Experimental details

Crystal data
Chemical formula	C₁₇H₂₂O₁₀
M_r	386.35
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	298
a, b, c (Å)	9.6848 (5), 10.5107 (5), 20.1765 (13)
V (Å³)	2053.8 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.28 × 0.27 × 0.24

Data collection
Diffractometer	Rigaku R-AXIS RAPID diffractometer
Absorption correction	Multi-scan (ABSCOR; Higashi 1995)
T_min, T_max	0.708, 0.979
No. of measured, independent and observed [I > 2σ(I)] reflections	11076, 2396, 2255
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.628

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.113, 1.06
No. of reflections	2396
No. of parameters	284
No. of restraints	4
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.15, −0.13

Computer programs: CrystalClear (Rigaku/MSC, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top

O1—C1	1.399 (3)	C1—C2	1.522 (3)
O1—C7	1.433 (3)	C2—C3	1.516 (3)
O2—C2	1.444 (3)	C3—C4	1.511 (3)
O3—C3	1.444 (3)	C4—C5	1.526 (3)
O4—C4	1.439 (3)	C5—C6	1.509 (3)
O5—C1	1.404 (3)	C7—C8	1.463 (4)
O5—C5	1.436 (3)	C8—C9	1.153 (5)
O6—C6	1.446 (3)

C1—O1—C7	113.41 (17)	C3—C4—C5	108.97 (18)
C1—O5—C5	113.68 (14)	O5—C5—C4	108.74 (16)
O5—C1—C2	112.21 (18)	O1—C7—C8	112.6 (2)
C3—C2—C1	110.30 (17)	C9—C8—C7	177.6 (4)
C4—C3—C2	109.74 (16)

C7—O1—C1—O5	61.2 (2)	C1—O5—C5—C6	−175.66 (18)
C7—O1—C1—C2	−175.8 (2)	C1—O5—C5—C4	61.0 (2)
C5—O5—C1—O1	61.9 (2)	C3—C4—C5—O5	−60.2 (2)
C5—O5—C1—C2	−57.5 (2)	C3—C4—C5—C6	−179.45 (17)
O1—C1—C2—O2	171.73 (17)	O5—C5—C6—O6	−61.9 (2)
O1—C1—C2—C3	−70.8 (2)	C4—C5—C6—O6	58.3 (2)
O5—C1—C2—C3	52.4 (2)	C1—O1—C7—C8	60.7 (3)
O2—C2—C3—O3	−54.7 (2)	H2—C2—O2—C10	−0.5
O2—C2—C3—C4	63.1 (2)	H3—C3—O3—C12A	36.1
C1—C2—C3—C4	−53.1 (2)	H4—C4—O4—C14	−4.4
O3—C3—C4—O4	−64.3 (2)	H3—C3—O3—C12B	4.0
C2—C3—C4—C5	57.6 (2)

Comparison of ¹³C NMR chemical shifts from the solid state and in solution in CDCl₃ (p.p.m.) top

State	C1	C2	C3	C4	C5	C6	OCH₂	qC	CH
Solid	93.5	70.8*	69.5*	63.3	69.0*	61.1	52.2	79.5	76.7
Solution	96.4	69.5	69.1*	66.2	69.0*	62.4	55.1	78.0	75.7

Note: (*) Assignments may be interchanged.

Solution NMR parameters (CDCl₃) top

Position	δ_H (p.p.m.)	³J_H,H+1 (Hz)	δ_C_═_O (p.p.m.)	³J_H,C_═_O (Hz)
1	5.01	1.7
2	5.25	3.3	170.03	3.6
3	5.32	10.0	169.92	3.2
4	5.28	9.4	169.78	3.6
5	4.00	2.4, 5.2
6	4.09	²J_H,H 12.2	170.7	3.2
6	4.27			2.5

Acknowledgements

This work was supported by a grant from NSERC to TBG. We thank Edgar Anderson for discussions of acetate conformations.

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