A novel chiral C₂ axially symmetric acenaphtho­quinone diketal

The crystal structure of the title compound, (-)-(4R,5R,4''R,5''R)-4,5,4'',5''-tetra­methyl­di­spiro­[1,3-dioxalane-2,1'(2'H)-acenaphthyl­ene-2',2''-1,3-dioxalane], C₂₀H₂₂O₄, contains mol­ecules separated by normal van der Waals distances. The dioxa­cyclo­pentane rings adopt envelope conformations and the naphthalene moiety is essentially planar while the two C atoms bonded to it lie 0.122 (8) and 0.105 (8) Å on opposite sides from its mean plane.

Key indicators

• Single-crystal X-ray study
• T = 200 K
• Mean [sigma](C-C) = 0.009 Å
• R factor = 0.040
• wR factor = 0.167
• Data-to-parameter ratio = 8.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



ABSMU_01  Alert C The ratio of given/expected absorption coefficient lies
          outside the range 0.99 <> 1.01
          Calculated value of mu =     0.087
          Value of mu given      =     0.090

STRVAL_01
         From the CIF: _refine_ls_abs_structure_Flack   -1.000
         From the CIF: _refine_ls_abs_structure_Flack_su    4.000
           Alert C Flack parameter is too small

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           25.00
         From the CIF: _reflns_number_total               1758
         Count of symmetry unique reflns         1748
         Completeness (_total/calc)            100.57%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured        10
         Fraction of Friedel pairs measured     0.006
         Are heavy atom types Z>Si present           no
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 2 Alert Level C = Please check

---

S1. Comment

Naphthalene–Cr(CO)₃ can be used to transfer Cr(CO)₃ to monoarenes (Kündig & Timms, 1977). In cases where the monoarene is prochiral, the use of a homochiral naphthalene–Cr(CO)₃ complex might be expected (depending on the actual mechanism of this transfer; Traylor et al., 1989; Howell et al., 1991) to result in some enantioselectivity in the formed monoarene complex. To simplify the number of possible Cr(CO)₃ isomers of a chiral naphthalene and to maximize the chiral environment for subsequent Cr(CO)₃ transfer, it was desirable to use C₂ axially symmetric chiral naphthalenes in this work. One potential candidate was the bis-acetal (III) (Simion, 1996). Acenaphthoquinone (I) was reacted with diol (II) to produce the bis-ketal (III). The X-ray crystal structure determination of (III) was undertaken for two reasons: (i) to verify that the bis-acetal (III) was actually formed; the bis-1,4-dioxane structure (IV) was also possible and NMR spectroscopy was not definitive in distinguishing (III) and (IV), and (ii) to determine the detailed conformation of (III) with regard to the steric differentiation between the two naphthalene faces.

The structure of (III) is composed of molecules (Fig. 1) separated by normal van der Waals distances. The dioxacyclopentane rings adopt C13- and C17-envelope conformations, with C13 and C17 0.543 (9) and 0.550 (10) Å, respectively, out of the planes formed by the remaining ring atoms. The naphthalene moiety in the acenaphthene ring is essentially planar, while the two C atoms bonded to it lie 0.122 (8) and 0.105 (8) Å on opposite sides from its mean plane. The molecular dimensions are as expected.

S2. Experimental

Acenaphthoquinone, (I), was refluxed (Dean-Stark trap) with 9 equivalents of (-)-(2R,3R)-butane-2,3-diol, (II), in toluene solvent (cat. p-toluenesulfonic acid) for 17 d, leading to (III), a bis-ketal product, which was purified by flash chromatography (SiO₂, 1:1 benzene–ethyl acetate), 80% yield, m.p. 478–479 K (from benzene–hexane), [α]_D²³ = -23.8 (c = 0.075, CHCl₃). GC–MS analysis of the crude material also showed the presence of a minor isomer.

S3. Refinement

The space group was uniquely determined from the systematic absences. All the H atoms were located from difference maps and were included at geometrically idealized positions, with C—H = 0.95–1.00 Å, in a riding mode with isotropic displacement parameters 1.2 (non-methyl) and 1.5 (methyl) times the displacement parameters of the atoms to which they were attached. An absolute structure was not established in this analysis since the absolute configuration of the starting material was already known.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1994); program(s) used to solve structure: SAPI91 (Fan, 1991); program(s) used to refine structure: SHELXS97 (Sheldrick, 1997); molecular graphics: TEXSAN; software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. ORTEPII (Johnson, 1976) drawing of (III). Displacement ellipsoids have been plotted at the 50% probability level.

(-)-(4R,5R,4''R,5''R)-4,5,4'',5''-Tetramethyldispiro[1,3-dioxalane- 2,1'(2'H)-acenaphthylene-2',2''-1,3-dioxalane]

Crystal data

C20H22O4	Dx = 1.264 Mg m^−3
Mr = 326.38	Mo Kα radiation, λ = 0.71069 Å
Orthorhombic, P212121	Cell parameters from 25 reflections
a = 9.799 (3) Å	θ = 10.0–15.0°
b = 19.331 (5) Å	µ = 0.09 mm^−1
c = 9.054 (3) Å	T = 200 K
V = 1715.0 (9) Å^3	Prismatic, colourless
Z = 4	0.50 × 0.21 × 0.13 mm
F(000) = 696

Data collection

Rigaku AFC-6S diffractometer	Rint = 0.00
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.0°
Graphite monochromator	h = 0→11
ω/2θ scans	k = 0→23
1758 measured reflections	l = 0→10
1758 independent reflections	3 standard reflections every 200 reflections
831 reflections with I > 2σ(I)	intensity decay: <0.5%

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	Riding
R[F^2 > 2σ(F^2)] = 0.040	w = 1/[σ^2(Fo^2) + (0.0835P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.167	(Δ/σ)max < 0.001
S = 1.00	Δρmax = 0.22 e Å^−3
1758 reflections	Δρmin = −0.24 e Å^−3
218 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.013 (3)
Primary atom site location: structure-invariant direct methods	Absolute structure: (Flack, 1983)
Secondary atom site location: difference Fourier map	Absolute structure parameter: −1 (4)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.4224 (4)	0.8113 (2)	0.1498 (5)	0.0382 (11)
O2	0.2437 (4)	0.7621 (2)	0.0262 (4)	0.0382 (12)
O3	0.2818 (5)	0.8308 (2)	0.3954 (4)	0.0396 (12)
O4	0.0994 (4)	0.8184 (2)	0.2423 (4)	0.0368 (11)
C1	0.2786 (6)	0.6664 (3)	0.3185 (6)	0.0330 (15)
C2	0.1912 (7)	0.7163 (3)	0.3759 (6)	0.0343 (16)
C3	0.1042 (7)	0.6992 (3)	0.4889 (7)	0.0417 (17)
H3	0.0432	0.7322	0.5269	0.050*
C4	0.1073 (8)	0.6331 (4)	0.5462 (7)	0.052 (2)
H4	0.0482	0.6219	0.6244	0.062*
C5	0.1956 (7)	0.5822 (4)	0.4917 (7)	0.0476 (19)
H5	0.1958	0.5377	0.5334	0.057*
C6	0.2844 (7)	0.5981 (3)	0.3737 (7)	0.0394 (17)
C7	0.3782 (7)	0.5544 (3)	0.3019 (8)	0.0457 (18)
H7	0.3869	0.5082	0.3332	0.055*
C8	0.4574 (7)	0.5777 (3)	0.1869 (8)	0.048 (2)
H8	0.5202	0.5473	0.1430	0.058*
C9	0.4475 (7)	0.6451 (4)	0.1335 (7)	0.0425 (18)
H9	0.5016	0.6594	0.0534	0.051*
C10	0.3567 (5)	0.6912 (3)	0.1997 (7)	0.0308 (15)
C11	0.3138 (6)	0.7633 (3)	0.1641 (6)	0.0354 (16)
C12	0.2172 (6)	0.7847 (3)	0.2969 (6)	0.0302 (14)
C13	0.4487 (6)	0.8185 (3)	−0.0069 (7)	0.0368 (16)
H13	0.5049	0.7790	−0.0405	0.044*
C14	0.3072 (6)	0.8118 (4)	−0.0709 (6)	0.0384 (16)
H14	0.2594	0.8567	−0.0614	0.046*
C15	0.5246 (7)	0.8837 (3)	−0.0339 (8)	0.059 (2)
H15A	0.6136	0.8809	0.0125	0.088*
H15B	0.4740	0.9222	0.0075	0.088*
H15C	0.5356	0.8904	−0.1394	0.088*
C16	0.2968 (8)	0.7876 (4)	−0.2260 (6)	0.066 (2)
H16A	0.2016	0.7858	−0.2550	0.099*
H16B	0.3367	0.7418	−0.2343	0.099*
H16C	0.3454	0.8193	−0.2901	0.099*
C17	0.2239 (7)	0.8971 (3)	0.3690 (7)	0.0408 (17)
H17	0.2700	0.9188	0.2834	0.049*
C18	0.0793 (7)	0.8804 (3)	0.3288 (8)	0.0438 (18)
H18	0.0271	0.8691	0.4192	0.053*
C19	0.2438 (7)	0.9423 (4)	0.5052 (7)	0.057 (2)
H19A	0.3405	0.9502	0.5208	0.085*
H19B	0.2056	0.9191	0.5908	0.085*
H19C	0.1980	0.9862	0.4908	0.085*
C20	0.0015 (8)	0.9315 (3)	0.2383 (9)	0.059 (2)
H20A	−0.0899	0.9141	0.2204	0.088*
H20B	0.0476	0.9385	0.1447	0.088*
H20C	−0.0039	0.9751	0.2910	0.088*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.033 (2)	0.046 (3)	0.036 (2)	−0.006 (2)	0.005 (2)	−0.001 (2)
O2	0.038 (3)	0.052 (3)	0.025 (2)	−0.006 (2)	−0.005 (2)	0.000 (2)
O3	0.040 (3)	0.039 (3)	0.039 (2)	0.003 (2)	−0.008 (2)	−0.009 (2)
O4	0.035 (2)	0.035 (2)	0.041 (2)	0.005 (2)	−0.004 (2)	−0.007 (2)
C1	0.026 (3)	0.051 (4)	0.022 (3)	−0.007 (3)	−0.003 (3)	0.001 (3)
C2	0.032 (3)	0.043 (4)	0.028 (3)	−0.004 (3)	−0.006 (3)	−0.001 (3)
C3	0.041 (4)	0.046 (4)	0.038 (4)	0.002 (4)	0.003 (4)	0.003 (4)
C4	0.052 (5)	0.070 (5)	0.034 (4)	−0.017 (5)	0.006 (4)	0.011 (4)
C5	0.048 (4)	0.046 (4)	0.049 (4)	−0.013 (4)	−0.006 (4)	0.019 (4)
C6	0.040 (4)	0.039 (4)	0.040 (4)	−0.008 (3)	−0.005 (4)	0.003 (3)
C7	0.053 (4)	0.033 (4)	0.051 (4)	0.008 (4)	−0.001 (4)	−0.002 (4)
C8	0.048 (4)	0.037 (4)	0.060 (5)	0.006 (3)	0.012 (4)	−0.011 (4)
C9	0.042 (4)	0.050 (5)	0.035 (4)	−0.001 (4)	0.002 (4)	−0.005 (4)
C10	0.022 (3)	0.035 (4)	0.035 (3)	−0.003 (3)	−0.003 (3)	−0.007 (3)
C11	0.032 (3)	0.051 (4)	0.024 (3)	−0.007 (3)	−0.002 (3)	−0.004 (3)
C12	0.023 (3)	0.037 (4)	0.031 (3)	0.003 (3)	−0.002 (3)	−0.007 (3)
C13	0.040 (4)	0.029 (3)	0.042 (4)	0.007 (3)	0.008 (3)	0.006 (3)
C14	0.031 (3)	0.042 (4)	0.042 (4)	0.010 (3)	0.006 (3)	0.007 (3)
C15	0.057 (5)	0.047 (5)	0.072 (5)	0.000 (4)	0.018 (5)	0.012 (4)
C16	0.061 (5)	0.107 (7)	0.030 (4)	0.016 (5)	0.001 (4)	0.006 (4)
C17	0.053 (4)	0.033 (4)	0.036 (4)	−0.007 (3)	0.010 (4)	−0.004 (3)
C18	0.040 (4)	0.050 (4)	0.041 (4)	−0.001 (4)	0.008 (4)	−0.010 (3)
C19	0.058 (5)	0.053 (4)	0.059 (5)	0.007 (4)	−0.007 (4)	−0.026 (4)
C20	0.070 (5)	0.037 (4)	0.070 (5)	0.014 (4)	−0.021 (4)	−0.008 (4)

Geometric parameters (Å, º)

O1—C11	1.418 (7)	C9—H9	0.9400
O1—C13	1.449 (7)	C10—C11	1.492 (9)
O2—C11	1.425 (7)	C11—C12	1.585 (8)
O2—C14	1.443 (7)	C13—C15	1.482 (8)
O3—C12	1.411 (7)	C13—C14	1.508 (9)
O3—C17	1.423 (7)	C13—H13	0.9900
O4—C12	1.415 (7)	C14—C16	1.483 (8)
O4—C18	1.444 (7)	C14—H14	0.9900
C1—C2	1.391 (8)	C15—H15A	0.9700
C1—C10	1.405 (8)	C15—H15B	0.9700
C1—C6	1.413 (8)	C15—H15C	0.9700
C2—C3	1.371 (8)	C16—H16A	0.9700
C2—C12	1.525 (8)	C16—H16B	0.9700
C3—C4	1.379 (9)	C16—H16C	0.9700
C3—H3	0.9400	C17—C18	1.499 (9)
C4—C5	1.400 (10)	C17—C19	1.524 (8)
C4—H4	0.9400	C17—H17	0.9900
C5—C6	1.411 (9)	C18—C20	1.493 (9)
C5—H5	0.9400	C18—H18	0.9900
C6—C7	1.408 (9)	C19—H19A	0.9700
C7—C8	1.374 (9)	C19—H19B	0.9700
C7—H7	0.9400	C19—H19C	0.9700
C8—C9	1.392 (9)	C20—H20A	0.9700
C8—H8	0.9400	C20—H20B	0.9700
C9—C10	1.395 (8)	C20—H20C	0.9700
C11—O1—C13	106.6 (5)	O1—C13—C14	101.8 (5)
C11—O2—C14	108.4 (4)	C15—C13—C14	118.1 (6)
C12—O3—C17	106.5 (5)	O1—C13—H13	109.1
C12—O4—C18	107.8 (4)	C15—C13—H13	109.1
C2—C1—C10	112.6 (6)	C14—C13—H13	109.1
C2—C1—C6	122.7 (6)	O2—C14—C16	109.7 (6)
C10—C1—C6	124.6 (6)	O2—C14—C13	102.7 (5)
C3—C2—C1	119.6 (6)	C16—C14—C13	117.0 (6)
C3—C2—C12	131.5 (6)	O2—C14—H14	109.0
C1—C2—C12	108.9 (5)	C16—C14—H14	109.0
C2—C3—C4	119.4 (6)	C13—C14—H14	109.0
C2—C3—H3	120.3	C13—C15—H15A	109.5
C4—C3—H3	120.3	C13—C15—H15B	109.5
C3—C4—C5	122.1 (7)	H15A—C15—H15B	109.5
C3—C4—H4	118.9	C13—C15—H15C	109.5
C5—C4—H4	118.9	H15A—C15—H15C	109.5
C4—C5—C6	119.7 (6)	H15B—C15—H15C	109.5
C4—C5—H5	120.2	C14—C16—H16A	109.5
C6—C5—H5	120.2	C14—C16—H16B	109.5
C7—C6—C5	128.5 (6)	H16A—C16—H16B	109.5
C7—C6—C1	115.1 (6)	C14—C16—H16C	109.5
C5—C6—C1	116.5 (6)	H16A—C16—H16C	109.5
C8—C7—C6	121.4 (6)	H16B—C16—H16C	109.5
C8—C7—H7	119.3	O3—C17—C18	102.9 (5)
C6—C7—H7	119.3	O3—C17—C19	109.2 (5)
C7—C8—C9	122.1 (7)	C18—C17—C19	116.2 (6)
C7—C8—H8	119.0	O3—C17—H17	109.4
C9—C8—H8	119.0	C18—C17—H17	109.4
C8—C9—C10	119.5 (6)	C19—C17—H17	109.4
C8—C9—H9	120.2	O4—C18—C20	108.7 (5)
C10—C9—H9	120.2	O4—C18—C17	100.4 (5)
C9—C10—C1	117.3 (6)	C20—C18—C17	118.3 (6)
C9—C10—C11	133.2 (6)	O4—C18—H18	109.6
C1—C10—C11	109.3 (5)	C20—C18—H18	109.6
O1—C11—O2	107.0 (4)	C17—C18—H18	109.6
O1—C11—C10	114.8 (5)	C17—C19—H19A	109.5
O2—C11—C10	108.0 (5)	C17—C19—H19B	109.5
O1—C11—C12	110.3 (5)	H19A—C19—H19B	109.5
O2—C11—C12	112.4 (5)	C17—C19—H19C	109.5
C10—C11—C12	104.3 (5)	H19A—C19—H19C	109.5
O3—C12—O4	107.2 (4)	H19B—C19—H19C	109.5
O3—C12—C2	109.0 (5)	C18—C20—H20A	109.5
O4—C12—C2	115.3 (5)	C18—C20—H20B	109.5
O3—C12—C11	112.1 (5)	H20A—C20—H20B	109.5
O4—C12—C11	110.0 (4)	C18—C20—H20C	109.5
C2—C12—C11	103.3 (5)	H20A—C20—H20C	109.5
O1—C13—C15	109.4 (5)	H20B—C20—H20C	109.5
C10—C1—C2—C3	177.5 (5)	C17—O3—C12—C2	−140.7 (5)
C6—C1—C2—C3	−1.3 (9)	C17—O3—C12—C11	105.5 (6)
C10—C1—C2—C12	−4.4 (7)	C18—O4—C12—O3	−10.4 (6)
C6—C1—C2—C12	176.8 (5)	C18—O4—C12—C2	111.2 (5)
C1—C2—C3—C4	1.5 (9)	C18—O4—C12—C11	−132.5 (5)
C12—C2—C3—C4	−176.1 (6)	C3—C2—C12—O3	68.7 (8)
C2—C3—C4—C5	−0.7 (10)	C1—C2—C12—O3	−109.1 (5)
C3—C4—C5—C6	−0.4 (10)	C3—C2—C12—O4	−51.8 (9)
C4—C5—C6—C7	−178.7 (7)	C1—C2—C12—O4	130.3 (5)
C4—C5—C6—C1	0.7 (9)	C3—C2—C12—C11	−171.9 (6)
C2—C1—C6—C7	179.7 (6)	C1—C2—C12—C11	10.3 (6)
C10—C1—C6—C7	1.0 (9)	O1—C11—C12—O3	−18.7 (7)
C2—C1—C6—C5	0.2 (9)	O2—C11—C12—O3	−138.0 (5)
C10—C1—C6—C5	−178.5 (5)	C10—C11—C12—O3	105.1 (5)
C5—C6—C7—C8	179.5 (7)	O1—C11—C12—O4	100.4 (5)
C1—C6—C7—C8	0.1 (9)	O2—C11—C12—O4	−19.0 (7)
C6—C7—C8—C9	−1.3 (10)	C10—C11—C12—O4	−135.8 (5)
C7—C8—C9—C10	1.3 (10)	O1—C11—C12—C2	−135.9 (5)
C8—C9—C10—C1	−0.3 (9)	O2—C11—C12—C2	104.7 (6)
C8—C9—C10—C11	−174.6 (6)	C10—C11—C12—C2	−12.1 (6)
C2—C1—C10—C9	−179.7 (5)	C11—O1—C13—C15	160.5 (5)
C6—C1—C10—C9	−0.9 (8)	C11—O1—C13—C14	34.9 (6)
C2—C1—C10—C11	−4.1 (7)	C11—O2—C14—C16	148.4 (6)
C6—C1—C10—C11	174.7 (5)	C11—O2—C14—C13	23.3 (6)
C13—O1—C11—O2	−21.3 (6)	O1—C13—C14—O2	−35.0 (6)
C13—O1—C11—C10	98.6 (5)	C15—C13—C14—O2	−154.7 (6)
C13—O1—C11—C12	−143.8 (5)	O1—C13—C14—C16	−155.2 (6)
C14—O2—C11—O1	−2.1 (6)	C15—C13—C14—C16	85.1 (8)
C14—O2—C11—C10	−126.3 (5)	C12—O3—C17—C18	33.7 (6)
C14—O2—C11—C12	119.1 (5)	C12—O3—C17—C19	157.7 (5)
C9—C10—C11—O1	−54.2 (9)	C12—O4—C18—C20	154.8 (5)
C1—C10—C11—O1	131.1 (5)	C12—O4—C18—C17	29.9 (6)
C9—C10—C11—O2	65.1 (8)	O3—C17—C18—O4	−38.4 (6)
C1—C10—C11—O2	−109.5 (5)	C19—C17—C18—O4	−157.6 (5)
C9—C10—C11—C12	−175.1 (6)	O3—C17—C18—C20	−156.4 (6)
C1—C10—C11—C12	10.3 (6)	C19—C17—C18—C20	84.3 (8)
C17—O3—C12—O4	−15.2 (6)