supplementary materials


is5321 scheme

Acta Cryst. (2013). E69, o1811    [ doi:10.1107/S1600536813031140 ]

(-)-Benzyl 2,3-dide­oxy-[beta]-D-erythro-hex-2-eno­pyran­oside

S. Ohba, H. Okazaki, Y. Ueda, K. Hanaya, M. Shoji and T. Sugai

Abstract top

In the title compound, C13H16O4, the six-membered ring of the sugar moiety shows a half-chair conformation. In the crystal, mol­ecules are connected via O-H...O hydrogen bonds, forming columns around twofold screw axes along the b-axis direction. There is a disorder of the benz­yloxy group, which has two possible orientations with the phenyl group lying on a common plane [site-occupancy factors = 0.589 (9) and 0.411 (9)].

Experimental top

Synthesis and crystallization top

To a solution of 1c (669 mg, 2.17 mmol) in CH3CN (22 ml) were added Cs2CO3 (1.41 g, 4.33 mmol) and BnOH (4.53 ml, 43.5 mmol) and the mixture was stirred for 8 h at room temperature. The mixture was diluted H2O and organic materials were extracted with CHCl3. The combined extract was washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was purified by silica gel column chromatography (20 g). Elution with hexane-EtOAc (2:1) afforded the title compound (I) as a colorless solid (414 mg, 81%). The plate-like crystals of (I) were grown by slow cooling of a t-butyl­methyl­ether/hexane solution from ca 340 K to the room temperature. The specific rotation [α]D of (I) at 295 K is -107° (c 1.33, EtOH).

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 1. The absolute structure was assigned based on the known absolute configuration around the C6 atom, which originated from (+)-D-glucose. In the absence of significant anomalous scattering effects, Friedel pairs were averaged before the final refinement. There is an orientational disorder of the benzyl­oxy group, where the split phenyl group moieties lie on a common plane. The site occupation factor of the major part (O4A, C11A—C17A) was refined to 58.9 (9)%. All the H atoms were positioned geometrically, and refined as riding, with C—H = 0.93–0.98 Å and O—H = 0.82 Å, and with Uiso(H) = 1.2Ueq(C,O). The hy­droxy groups were allowed to rotate but not to tip.

Comment top

Glycosidic bond formation on glycals such as (1a in Fig. 3) accompanied with the migration of double bond from C1—C2 to C2—C3 had been recognized as Ferrier reaction to give 2-eno­pyran­osides (2) (Ferrier & Prasad, 1969; Noshita et al., 1995). Generally, α-glycosides predominate by the well known oxygen anomeric stabilizing effect, and the anomeric stereochemistry was elucidated by X-ray structure analysis of 2a (Wingert et al., 1984). In contrast, Di Bussolo et al.(2002, 2004) have demonstrated unique β-selective approach, starting from glycals such as 3 with leaving group at C4—OH. By neighboring group participation with free C3—OH, via an epoxide inter­mediate (4), Ferrier-like rearrangement occurred to give 5. Their proposed mechanism is shown in Fig. 3. In this case, a hydrogen bonding between ep­oxy ring in 4 and nucleophile dominates the stereochemistry to β rather than α. We submitted 3,6-di-O-acetyl-D-glucal (1b), which is very easily available by an enzymatic regioselective acyl­ation of D-glucal (Calveras et al., 2010), to Crotti's protocol. Introduction of methyl­sulfonyl group on free C4—OH (1c) and subsequent nuleophilic attack with benzyl alcohol provided the title compound, (I)(81%).

In the present study, the regio- and stereochemistry of (I) has been determined, although there is a complicated disorder. The benzyl­oxy group has two possible orientations, O4A/C11A—C17A and O4B/C11B—C17B, and their site occupation factors are 58.9 (9) and 41.1 (9)%, respectively. The C10—O4A and C10—O4B bond directions make an angle of 25.4 (7)°.

Related literature top

For the phenolic Ferrier reaction, see: Ferrier & Prasad (1969); Noshita et al. (1995). For the structure of the related compound α-glycoside, see: Wingert et al. (1984). For the synthesis of β-glycoside, see: Di Bussolo et al. (2002, 2004). For the enzymatic regioselective acylation of D-glucal, see: Calveras et al. (2010).

Computing details top

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999); cell refinement: WinAFC Diffractometer Control Software (Rigaku, 1999); data reduction: CrystalStructure (Rigaku, 2010); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: CrystalStructure (Rigaku, 2010).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound with anisotropic displacement parameters drawn at the 30% probability level. The minor part of the disordered benzyloxy group was omitted for clarity.
[Figure 2] Fig. 2. Crystal packing viewed along the b axis with intermolecular O—H···O hydrogen bonds as dashed lines. The minor part of the disordered benzyloxy group was omitted for clarity.
[Figure 3] Fig. 3. Ferrier reaction and synthesis of the title compound.
(-)-Benzyl 2,3-dideoxy-β-D-erythro-hex-2-enopyranoside top
Crystal data top
C13H16O4F(000) = 252.00
Mr = 236.26Dx = 1.254 Mg m3
Monoclinic, P21Melting point = 353–354 K
Hall symbol: P 2ybMo Kα radiation, λ = 0.71069 Å
a = 19.500 (9) ÅCell parameters from 25 reflections
b = 5.291 (2) Åθ = 10.1–12.5°
c = 6.0809 (15) ŵ = 0.09 mm1
β = 94.27 (3)°T = 292 K
V = 625.7 (4) Å3Plate, colorless
Z = 20.60 × 0.40 × 0.20 mm
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.034
Radiation source: Rigaku rotating Mo anodeθmax = 27.5°
Graphite plate monochromatorh = 925
ω–2θ scansk = 06
1713 measured reflectionsl = 77
1585 independent reflections3 standard reflections every 150 reflections
786 reflections with F2 > 2σ(F2) intensity decay: 0.8%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.056H-atom parameters constrained
wR(F2) = 0.255 w = 1/[σ2(Fo2) + (0.1473P)2 + 0.0601P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
1579 reflectionsΔρmax = 0.16 e Å3
193 parametersΔρmin = 0.17 e Å3
33 restraintsAbsolute structure: see text
Primary atom site location: structure-invariant direct methods
Crystal data top
C13H16O4V = 625.7 (4) Å3
Mr = 236.26Z = 2
Monoclinic, P21Mo Kα radiation
a = 19.500 (9) ŵ = 0.09 mm1
b = 5.291 (2) ÅT = 292 K
c = 6.0809 (15) Å0.60 × 0.40 × 0.20 mm
β = 94.27 (3)°
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.034
1713 measured reflectionsθmax = 27.5°
1585 independent reflections3 standard reflections every 150 reflections
786 reflections with F2 > 2σ(F2) intensity decay: 0.8%
Refinement top
R[F2 > 2σ(F2)] = 0.056H-atom parameters constrained
wR(F2) = 0.255Δρmax = 0.16 e Å3
S = 1.04Δρmin = 0.17 e Å3
1579 reflectionsAbsolute structure: see text
193 parametersAbsolute structure parameter: ?
33 restraintsRogers parameter: ?
Special details top

Experimental. Spectroscopic data: IR ν max: 3292, 2937, 2872, 1377, 1325, 1176, 1144, 1122, 1051, 970, 951, 876, 787, 744, 696 cm-1; 1H NMR (CDCl3): δ = 7.26–7.40 (m, 5H), 6.14 (ddd, J = 1.3, 4.6, 10.0 Hz, 1H), 5.89 (ddd, J = 1.0, 1.1, 10.0 Hz, 1H), 5.18 (ddd, J = 1.1, 1.3, 1.5 Hz, 1H), 4.92 (d, J = 11.8 Hz, 1H), 4.70 (d, J = 11.8 Hz, 1H), 4.02–4.09 (m, 1H), 3.97 (ddd, J = 5.9, 6.7, 12.0 Hz, 1H), 3.88 (ddd, J = 4.3, 7.3, 12.0 Hz, 1H), 3.79 (ddd, J = 3.1, 4.3, 6.7 Hz, 1H), 2.21 (dd, J = 5.9, 7.3 Hz, 1H), 1.97 (d, J = 10.6 Hz, 1H); 13C NMR (CDCl3): δ = 137.2, 130.9, 130.2, 128.4, 128.0, 127.9, 96.5, 75.1, 70.3, 62.9, 62.5.

Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F2. R-factor (gt) are based on F. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.3098 (2)0.1914 (7)0.7411 (7)0.0920 (13)
O20.4326 (4)0.2905 (9)0.9178 (11)0.152 (3)
O30.4652 (2)0.2679 (10)0.7637 (8)0.0988 (14)
O4A0.2323 (7)0.485 (3)0.5340 (18)0.090 (4)0.589 (9)
O4B0.2402 (8)0.476 (4)0.638 (2)0.068 (4)0.411 (9)
C50.3777 (5)0.1093 (15)0.9332 (13)0.116 (3)
C60.3606 (3)0.0062 (11)0.7108 (10)0.0822 (15)
C70.4216 (3)0.1300 (14)0.6082 (9)0.0837 (16)
C80.3960 (3)0.2985 (17)0.4253 (8)0.0933 (19)
C90.3317 (3)0.3656 (15)0.3939 (10)0.096 (2)
C100.2796 (3)0.2768 (14)0.5335 (12)0.0946 (17)
C11A0.1683 (5)0.409 (3)0.605 (3)0.097 (4)0.589 (9)
C11B0.1941 (7)0.406 (4)0.797 (4)0.107 (6)0.411 (9)
C12A0.1400 (7)0.603 (3)0.754 (2)0.078 (4)0.589 (9)
C12B0.1432 (11)0.611 (4)0.826 (4)0.078 (4)0.411 (9)
C13A0.1743 (7)0.635 (3)0.960 (2)0.108 (4)0.589 (9)
C13B0.1432 (12)0.747 (5)1.019 (4)0.108 (4)0.411 (9)
C14A0.1520 (9)0.811 (4)1.107 (3)0.153 (8)0.589 (9)
C14B0.0960 (16)0.938 (7)1.038 (5)0.153 (8)0.411 (9)
C15A0.0936 (10)0.947 (4)1.041 (3)0.143 (8)0.589 (9)
C15B0.0485 (15)0.990 (5)0.867 (4)0.143 (8)0.411 (9)
C16A0.0592 (8)0.927 (3)0.837 (3)0.109 (4)0.589 (9)
C16B0.0481 (10)0.852 (4)0.674 (3)0.109 (4)0.411 (9)
C17A0.0842 (9)0.750 (3)0.696 (3)0.095 (4)0.589 (9)
C17B0.0940 (15)0.661 (5)0.659 (5)0.095 (4)0.411 (9)
H20.46790.23550.98220.1820*
H30.45430.41760.75920.1185*
H510.39190.02151.03870.1391*
H520.33740.19260.98360.1391*
H60.34110.12430.61030.0986*
H70.44910.00400.54630.1005*
H80.42710.35890.32910.1120*
H90.31880.47430.27790.1150*
H10A0.25580.13360.45960.1135*0.589 (9)
H10B0.24960.14900.46010.1135*0.411 (9)
H11A0.17370.24990.68320.1165*0.589 (9)
H11B0.13610.38360.47790.1165*0.589 (9)
H11C0.21970.37250.93650.1280*0.411 (9)
H11D0.17010.25280.74940.1280*0.411 (9)
H13A0.21270.53601.00060.1298*0.589 (9)
H13B0.17500.71051.13650.1298*0.411 (9)
H14A0.17530.83671.24420.1836*0.589 (9)
H14B0.09651.03231.16720.1836*0.411 (9)
H15A0.07671.05981.14090.1720*0.589 (9)
H15B0.01641.11820.88120.1720*0.411 (9)
H16A0.02111.02640.79620.1307*0.589 (9)
H16B0.01680.88930.55550.1307*0.411 (9)
H17A0.06210.73110.55640.1141*0.589 (9)
H17B0.09200.56250.53240.1141*0.411 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.089 (3)0.071 (3)0.121 (3)0.007 (2)0.040 (3)0.013 (3)
O20.198 (6)0.072 (3)0.169 (5)0.023 (4)0.094 (5)0.033 (3)
O30.083 (3)0.091 (3)0.117 (3)0.003 (3)0.029 (2)0.023 (3)
O4A0.079 (6)0.079 (5)0.111 (8)0.007 (5)0.009 (7)0.007 (8)
O4B0.051 (6)0.067 (6)0.087 (9)0.012 (5)0.010 (7)0.010 (9)
C50.132 (6)0.088 (5)0.128 (5)0.001 (5)0.010 (5)0.019 (5)
C60.089 (4)0.060 (3)0.097 (4)0.007 (3)0.003 (3)0.022 (3)
C70.076 (3)0.093 (4)0.082 (3)0.020 (3)0.000 (3)0.032 (3)
C80.080 (4)0.128 (6)0.073 (3)0.004 (4)0.012 (3)0.012 (4)
C90.086 (4)0.118 (6)0.083 (3)0.005 (4)0.001 (3)0.008 (4)
C100.067 (3)0.075 (4)0.141 (5)0.010 (4)0.005 (4)0.015 (4)
C11A0.057 (5)0.094 (8)0.141 (9)0.013 (6)0.016 (6)0.026 (8)
C11B0.060 (8)0.116 (13)0.146 (15)0.024 (9)0.023 (9)0.042 (13)
C12A0.062 (4)0.084 (4)0.088 (10)0.003 (4)0.002 (6)0.018 (6)
C12B0.062 (4)0.084 (4)0.088 (10)0.003 (4)0.002 (6)0.018 (6)
C13A0.107 (9)0.109 (10)0.106 (8)0.002 (7)0.009 (7)0.000 (8)
C13B0.107 (9)0.109 (10)0.106 (8)0.002 (7)0.009 (7)0.000 (8)
C14A0.159 (14)0.19 (2)0.107 (10)0.077 (16)0.007 (9)0.040 (11)
C14B0.159 (14)0.19 (2)0.107 (10)0.077 (16)0.007 (9)0.040 (11)
C15A0.169 (16)0.104 (10)0.171 (17)0.018 (11)0.109 (13)0.011 (11)
C15B0.169 (16)0.104 (10)0.171 (17)0.018 (11)0.109 (13)0.011 (11)
C16A0.096 (7)0.100 (9)0.134 (11)0.022 (7)0.031 (8)0.012 (7)
C16B0.096 (7)0.100 (9)0.134 (11)0.022 (7)0.031 (8)0.012 (7)
C17A0.076 (7)0.087 (13)0.121 (7)0.032 (8)0.004 (6)0.004 (8)
C17B0.076 (7)0.087 (13)0.121 (7)0.032 (8)0.004 (6)0.004 (8)
Geometric parameters (Å, º) top
O1—C61.416 (8)C16B—C17B1.36 (4)
O1—C101.426 (8)O2—H20.820
O2—C51.445 (11)O3—H30.820
O3—C71.424 (8)C5—H510.970
O4A—C101.438 (17)C5—H520.970
O4A—C11A1.409 (18)C6—H60.980
O4B—C101.477 (19)C7—H70.980
O4B—C11B1.42 (3)C8—H80.930
C5—C61.499 (10)C9—H90.930
C6—C71.531 (9)C10—H10A0.980
C7—C81.483 (9)C10—H10B0.980
C8—C91.304 (9)C11A—H11A0.970
C9—C101.449 (9)C11A—H11B0.970
C11A—C12A1.499 (19)C11B—H11C0.970
C11B—C12B1.49 (3)C11B—H11D0.970
C12A—C13A1.388 (18)C13A—H13A0.930
C12A—C17A1.36 (3)C13B—H13B0.930
C12B—C13B1.38 (3)C14A—H14A0.930
C12B—C17B1.37 (4)C14B—H14B0.930
C13A—C14A1.38 (3)C15A—H15A0.930
C13B—C14B1.38 (4)C15B—H15B0.930
C14A—C15A1.38 (3)C16A—H16A0.930
C14B—C15B1.37 (4)C16B—H16B0.930
C15A—C16A1.37 (3)C17A—H17A0.930
C15B—C16B1.39 (3)C17B—H17B0.930
C16A—C17A1.38 (3)
C6—O1—C10110.5 (5)C7—C6—H6108.989
C10—O4A—C11A111.4 (12)O3—C7—H7108.061
C10—O4B—C11B118.8 (16)C6—C7—H7108.071
O2—C5—C6109.1 (7)C8—C7—H7108.069
O1—C6—C5106.0 (6)C7—C8—H8118.624
O1—C6—C7109.3 (5)C9—C8—H8118.631
C5—C6—C7114.5 (6)C8—C9—H9118.863
O3—C7—C6113.1 (5)C10—C9—H9118.877
O3—C7—C8109.9 (6)O1—C10—H10A108.127
C6—C7—C8109.5 (5)O1—C10—H10B112.184
C7—C8—C9122.7 (6)O4A—C10—H10A108.127
C8—C9—C10122.3 (6)O4B—C10—H10B112.183
O1—C10—O4A117.6 (7)C9—C10—H10A108.128
O1—C10—O4B92.3 (7)C9—C10—H10B112.184
O1—C10—C9111.1 (5)O4A—C11A—H11A109.342
O4A—C10—C9103.3 (8)O4A—C11A—H11B109.349
O4B—C10—C9115.4 (9)C12A—C11A—H11A109.342
O4A—C11A—C12A111.4 (11)C12A—C11A—H11B109.335
O4B—C11B—C12B110.7 (18)H11A—C11A—H11B107.980
C11A—C12A—C13A117.0 (12)O4B—C11B—H11C109.503
C11A—C12A—C17A123.9 (12)O4B—C11B—H11D109.498
C13A—C12A—C17A119.1 (14)C12B—C11B—H11C109.496
C11B—C12B—C13B121.7 (19)C12B—C11B—H11D109.495
C11B—C12B—C17B119 (2)H11C—C11B—H11D108.069
C13B—C12B—C17B119 (2)C12A—C13A—H13A119.650
C12A—C13A—C14A120.7 (13)C14A—C13A—H13A119.655
C12B—C13B—C14B120 (2)C12B—C13B—H13B120.088
C13A—C14A—C15A117.1 (15)C14B—C13B—H13B120.082
C13B—C14B—C15B120 (3)C13A—C14A—H14A121.432
C14A—C15A—C16A124.1 (18)C15A—C14A—H14A121.427
C14B—C15B—C16B120 (3)C13B—C14B—H14B119.853
C15A—C16A—C17A116.3 (15)C15B—C14B—H14B119.850
C15B—C16B—C17B119 (2)C14A—C15A—H15A117.945
C12A—C17A—C16A122.6 (15)C16A—C15A—H15A117.953
C12B—C17B—C16B122 (3)C14B—C15B—H15B120.031
C5—O2—H2109.474C16B—C15B—H15B120.027
C7—O3—H3109.475C15A—C16A—H16A121.839
O2—C5—H51109.847C17A—C16A—H16A121.842
O2—C5—H52109.853C15B—C16B—H16B120.433
C6—C5—H51109.854C17B—C16B—H16B120.424
C6—C5—H52109.864C12A—C17A—H17A118.712
H51—C5—H52108.286C16A—C17A—H17A118.718
O1—C6—H6108.978C12B—C17B—H17B119.115
C5—C6—H6108.981C16B—C17B—H17B119.099
C6—O1—C10—O4A173.3 (5)C8—C9—C10—O4A147.8 (7)
C6—O1—C10—O4B173.0 (4)C8—C9—C10—O4B124.1 (7)
C6—O1—C10—C954.6 (6)O4A—C11A—C12A—C13A68.8 (15)
C10—O1—C6—C5168.0 (4)O4A—C11A—C12A—C17A109.9 (13)
C10—O1—C6—C768.1 (5)O4B—C11B—C12B—C13B111.9 (19)
C10—O4A—C11A—C12A139.3 (9)O4B—C11B—C12B—C17B70 (2)
C11A—O4A—C10—O174.9 (11)C11A—C12A—C13A—C14A179.4 (11)
C11A—O4A—C10—O4B75.6 (14)C11A—C12A—C17A—C16A179.8 (12)
C11A—O4A—C10—C9162.3 (9)C13A—C12A—C17A—C16A2 (3)
C10—O4B—C11B—C12B160.8 (10)C17A—C12A—C13A—C14A1 (2)
C11B—O4B—C10—O158.0 (13)C11B—C12B—C13B—C14B178.8 (17)
C11B—O4B—C10—O4A121 (3)C11B—C12B—C17B—C16B177.4 (19)
C11B—O4B—C10—C9172.7 (11)C13B—C12B—C17B—C16B4 (4)
O2—C5—C6—O1176.5 (5)C17B—C12B—C13B—C14B3 (4)
O2—C5—C6—C756.0 (7)C12A—C13A—C14A—C15A2 (3)
O1—C6—C7—O377.9 (6)C12B—C13B—C14B—C15B1 (4)
O1—C6—C7—C845.0 (6)C13A—C14A—C15A—C16A3 (3)
C5—C6—C7—O340.7 (8)C13B—C14B—C15B—C16B1 (5)
C5—C6—C7—C8163.7 (5)C14A—C15A—C16A—C17A3 (3)
O3—C7—C8—C9111.7 (7)C14B—C15B—C16B—C17B2 (4)
C6—C7—C8—C913.0 (9)C15A—C16A—C17A—C12A0 (3)
C7—C8—C9—C101.1 (11)C15B—C16B—C17B—C12B4 (4)
C8—C9—C10—O120.8 (10)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O3i0.821.952.692 (8)151
O3—H3···O2ii0.821.892.614 (8)147
Symmetry codes: (i) x+1, y1/2, z+2; (ii) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O3i0.821.952.692 (8)151
O3—H3···O2ii0.821.892.614 (8)147
Symmetry codes: (i) x+1, y1/2, z+2; (ii) x, y+1, z.
Acknowledgements top

This work was supported by the Keio Gijuku Academic Development Funds.

references
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