(6R*,10R*)-Dimethyl 1,4-dioxaspiro­[4.5]decane-6,10-dicarboxyl­ate

Abstract

The title compound, C₁₂H₁₈O₆, is in the usual chair conformation with the two ester functions in a 1,3-trans orientation. With a value of 1.439 (2) Å, the pseudo-axial C—O bond of the 1,3-dioxolane ring is slightly longer than the corresponding equatorial C—O bond of 1.424 (3) Å. The O—C—O angle of the dioxolane ring is 106.25 (17)°.

Related literature  

The starting material (1R,3S)-dimethyl 2-oxocyclo­hexane-1,3-dicarboxyl­ate was prepared following a known procedure (Blicke & McCarty, 1959 ▶). Alternative methods for the synthesis of this coumpound include alkyl­ation of cyclo­hexa­none (Balasubrahmanyam & Balasubramanian, 1969 ▶; Beckman & Munshi, 2011 ▶). Synthesis and characterization of a related 1,3-trans-dicarboxyl­ate cyclo­hexa­none has been reported (Scaric & Turjak-Cebic, 1982 ▶). The acetal formation follows standard procedures (Wuts & Greene, 2007 ▶).

Experimental  

Crystal data  

• C₁₂H₁₈O₆

• M _r = 258.26

• Monoclinic,

• a = 8.6243 (9) Å

• b = 7.3203 (6) Å

• c = 10.1704 (9) Å

• β = 91.719 (8)°

• V = 641.79 (10) ų

• Z = 2

• Mo Kα radiation

• μ = 0.11 mm⁻¹

• T = 293 K

• 0.2 × 0.2 × 0.05 mm

Data collection  

• Agilent Xcalibur Sapphire3 diffractometer

• Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T _min = 0.919, T _max = 1.000

• 5645 measured reflections

• 2717 independent reflections

• 2329 reflections with I > 2σ(I)

• R _int = 0.025

Refinement  

• R[F ² > 2σ(F ²)] = 0.047

• wR(F ²) = 0.148

• S = 1.03

• 2717 reflections

• 163 parameters

• 2 restraints

• H-atom parameters constrained

• Δρ_max = 0.31 e Å⁻³

• Δρ_min = −0.23 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalMaker (CrystalMaker, 2011 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

Comment

The cyclohexane ring is in the usual chair conformation. All intramolecular distances and angles display expected values. The dioxolane occupies a pseudo-twist form oriented towards the axial ester group of the cyclohexane ring. Presumably to reduce unfavorable interactions with the carbonyl group of the equatorial ester moiety.

Experimental

(1R,3S)-dimethyl 2-oxocyclohexane-1,3-dicarboxylate (0.5 g, 2.5 mmol) was dissolved in toluene (10 mL). Ethylene glycol (1.6 g, 25.7 mmol) and a catalytic amount of p-toluene sulfonic acid were then added sequentially. The vessel was fitted with a Dean-Stark trap, heated to reflux for 3 h, and then cooled to RT. The reaction mixture was washed with NaHCO₃ (10 ml, sat. aq.) and water (10 ml). The organic phase was dried (MgSO₄), filtered, and concentrated under reduced pressure. ¹H NMR of the crude shows a single diastereomer. The crude product was purified by flash chromatography (6.25% EtOAc/pet. ether) to give (6R*,10R*)dimethyl-1,4-dioxosparo[4,5]decane-6,10-dicarboxylate as a colorless oil (0.30 g, 46%), which crystallized under vaccuum upon standing.

R_f: 0.3 in 6.25% EtOAc/pet. ether ¹H-NMR: (400 MHz, CDCl₃) δ: 4.0–3.8 (m, 4H), 3.69 (s, 6H), 3.17 (t, 2H), 2.6 (dd, J = 8, 2H), 2.0–1.8 (m, 2H) p.p.m.. ¹³C-NMR: (101 MHz, CDCl₃) δ: 66.2, 65.1, 52.1, 51.8, 51.7, 47.5, 27.1, 26.6, 23.5, 19.8 p.p.m.. IR: (CHCl₃, film): 1727 (s), 1434 (m), 1161 (s) cm^-1.

Refinement

The H atoms were positioned geometrically and treated as riding on their parent atoms with C–H distances of 0.93–0.97 Å, and U_iso(H) = 1.2 U_eq. The highest difference peak in the Fourier map is located 0.87 Å from C12 and the lowest is located 0.30 Å from H12B.

Figures

Fig. 1.

The molecular structure of the title compound with atom labels and 30% probability displacement ellipsoids. H-atoms were omitted for clarity.

Crystal data

C12H18O6	F(000) = 276
Mr = 258.26	Dx = 1.336 Mg m−3
Monoclinic, Pc	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P -2yc	Cell parameters from 1887 reflections
a = 8.6243 (9) Å	θ = 2.8–28.6°
b = 7.3203 (6) Å	µ = 0.11 mm−1
c = 10.1704 (9) Å	T = 293 K
β = 91.719 (8)°	Plate, colourless
V = 641.79 (10) Å3	0.2 × 0.2 × 0.05 mm
Z = 2

Data collection

Agilent Xcalibur Sapphire3 diffractometer	2717 independent reflections
Radiation source: Enhance (Mo) X-ray Source	2329 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.025
Detector resolution: 16.1829 pixels mm-1	θmax = 28.7°, θmin = 2.8°
ω scans	h = −10→10
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011)	k = −9→9
Tmin = 0.919, Tmax = 1.000	l = −13→13
5645 measured reflections

Refinement

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.148	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.1P)2] where P = (Fo2 + 2Fc2)/3
2717 reflections	(Δ/σ)max < 0.001
163 parameters	Δρmax = 0.31 e Å−3
2 restraints	Δρmin = −0.23 e Å−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.4569 (2)	0.2366 (3)	0.86367 (19)	0.0350 (5)
O1	0.2305 (3)	0.1361 (4)	1.0635 (2)	0.0837 (8)
C2	0.2830 (3)	0.1979 (3)	0.8327 (2)	0.0397 (5)
H2	0.2775	0.1093	0.7605	0.048*
O2	0.0836 (3)	0.0069 (3)	0.9057 (2)	0.0618 (6)
C3	0.1999 (3)	0.3712 (4)	0.7846 (3)	0.0527 (6)
H3A	0.0899	0.3460	0.7733	0.063*
H3B	0.2388	0.4053	0.6995	0.063*
O3	0.7232 (3)	0.5536 (4)	0.9408 (3)	0.0847 (8)
O4	0.7037 (2)	0.3362 (3)	1.09499 (18)	0.0544 (5)
C4	0.2227 (4)	0.5314 (4)	0.8801 (3)	0.0589 (7)
H4A	0.1742	0.6400	0.8427	0.071*
H4B	0.1728	0.5039	0.9620	0.071*
O5	0.52831 (19)	0.2833 (2)	0.74210 (15)	0.0452 (4)
C5	0.3944 (4)	0.5677 (3)	0.9073 (3)	0.0535 (7)
H5A	0.4059	0.6666	0.9703	0.064*
H5B	0.4420	0.6057	0.8265	0.064*
O6	0.53266 (19)	0.0753 (2)	0.91042 (16)	0.0431 (4)
C6	0.4790 (3)	0.3956 (3)	0.9621 (2)	0.0398 (5)
H6	0.4301	0.3607	1.0441	0.048*
C7	0.2023 (3)	0.1132 (4)	0.9483 (2)	0.0442 (5)
C8	0.6476 (3)	0.4376 (4)	0.9939 (2)	0.0473 (6)
C9	−0.0086 (5)	−0.0765 (5)	1.0061 (4)	0.0781 (10)
H9A	−0.0899	−0.1481	0.9651	0.117*
H9B	−0.0533	0.0171	1.0591	0.117*
H9C	0.0562	−0.1539	1.0606	0.117*
C10	0.8590 (4)	0.3810 (5)	1.1422 (4)	0.0701 (9)
H10A	0.8881	0.3015	1.2138	0.105*
H10B	0.8617	0.5054	1.1719	0.105*
H10C	0.9301	0.3657	1.0722	0.105*
C11	0.6241 (5)	0.1332 (5)	0.7054 (3)	0.0690 (8)
H11A	0.5974	0.0938	0.6165	0.083*
H11B	0.7326	0.1685	0.7093	0.083*
C12	0.5965 (6)	−0.0107 (5)	0.7970 (4)	0.0818 (12)
H12A	0.6926	−0.0730	0.8208	0.098*
H12B	0.5241	−0.0990	0.7594	0.098*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0413 (12)	0.0341 (10)	0.0298 (10)	0.0001 (8)	0.0028 (8)	0.0031 (8)
O1	0.0846 (17)	0.124 (2)	0.0432 (11)	−0.0515 (15)	0.0057 (10)	0.0031 (12)
C2	0.0429 (12)	0.0414 (12)	0.0346 (11)	−0.0009 (9)	−0.0037 (8)	−0.0019 (9)
O2	0.0594 (12)	0.0623 (12)	0.0638 (12)	−0.0207 (9)	0.0007 (9)	−0.0022 (9)
C3	0.0543 (15)	0.0568 (15)	0.0465 (14)	0.0105 (12)	−0.0066 (11)	0.0056 (11)
O3	0.0750 (16)	0.0944 (18)	0.0845 (17)	−0.0420 (15)	0.0001 (12)	0.0270 (14)
O4	0.0454 (10)	0.0592 (11)	0.0580 (11)	−0.0120 (8)	−0.0054 (8)	0.0028 (9)
C4	0.0665 (19)	0.0498 (14)	0.0601 (16)	0.0181 (13)	−0.0012 (13)	0.0003 (13)
O5	0.0594 (11)	0.0409 (8)	0.0360 (8)	0.0035 (7)	0.0103 (7)	0.0046 (7)
C5	0.0700 (19)	0.0319 (11)	0.0586 (16)	0.0019 (11)	0.0038 (13)	−0.0062 (11)
O6	0.0502 (10)	0.0344 (8)	0.0445 (9)	0.0041 (7)	−0.0009 (7)	0.0060 (7)
C6	0.0458 (13)	0.0375 (11)	0.0364 (11)	−0.0049 (9)	0.0048 (9)	−0.0009 (9)
C7	0.0359 (12)	0.0505 (13)	0.0459 (13)	−0.0015 (9)	−0.0030 (9)	−0.0030 (10)
C8	0.0532 (15)	0.0479 (13)	0.0412 (12)	−0.0141 (11)	0.0058 (10)	−0.0059 (10)
C9	0.073 (2)	0.069 (2)	0.093 (3)	−0.0289 (17)	0.0185 (18)	−0.0040 (18)
C10	0.0461 (17)	0.086 (2)	0.078 (2)	−0.0110 (15)	−0.0106 (14)	−0.0074 (18)
C11	0.087 (2)	0.0631 (18)	0.0581 (17)	0.0159 (16)	0.0190 (15)	−0.0070 (15)
C12	0.107 (3)	0.0574 (18)	0.082 (2)	0.0358 (18)	0.031 (2)	0.0060 (16)

Geometric parameters (Å, º)

C1—O6	1.424 (3)	O5—C11	1.431 (4)
C1—O5	1.439 (2)	C5—C6	1.551 (4)
C1—C6	1.544 (3)	C5—H5A	0.9700
C1—C2	1.549 (3)	C5—H5B	0.9700
O1—C7	1.201 (3)	O6—C12	1.438 (4)
C2—C7	1.516 (4)	C6—C8	1.511 (4)
C2—C3	1.530 (3)	C6—H6	0.9800
C2—H2	0.9800	C9—H9A	0.9600
O2—C7	1.347 (3)	C9—H9B	0.9600
O2—C9	1.448 (4)	C9—H9C	0.9600
C3—C4	1.531 (4)	C10—H10A	0.9600
C3—H3A	0.9700	C10—H10B	0.9600
C3—H3B	0.9700	C10—H10C	0.9600
O3—C8	1.208 (3)	C11—C12	1.431 (5)
O4—C8	1.346 (3)	C11—H11A	0.9700
O4—C10	1.446 (3)	C11—H11B	0.9700
C4—C5	1.522 (4)	C12—H12A	0.9700
C4—H4A	0.9700	C12—H12B	0.9700
C4—H4B	0.9700
O6—C1—O5	106.25 (17)	C8—C6—C5	110.5 (2)
O6—C1—C6	111.21 (17)	C1—C6—C5	109.36 (19)
O5—C1—C6	109.28 (17)	C8—C6—H6	107.9
O6—C1—C2	110.39 (17)	C1—C6—H6	107.9
O5—C1—C2	107.80 (17)	C5—C6—H6	107.9
C6—C1—C2	111.70 (18)	O1—C7—O2	121.6 (2)
C7—C2—C3	111.5 (2)	O1—C7—C2	128.0 (2)
C7—C2—C1	112.39 (17)	O2—C7—C2	110.4 (2)
C3—C2—C1	110.79 (19)	O3—C8—O4	122.8 (2)
C7—C2—H2	107.3	O3—C8—C6	125.2 (3)
C3—C2—H2	107.3	O4—C8—C6	111.9 (2)
C1—C2—H2	107.3	O2—C9—H9A	109.5
C7—O2—C9	116.4 (2)	O2—C9—H9B	109.5
C2—C3—C4	112.48 (19)	H9A—C9—H9B	109.5
C2—C3—H3A	109.1	O2—C9—H9C	109.5
C4—C3—H3A	109.1	H9A—C9—H9C	109.5
C2—C3—H3B	109.1	H9B—C9—H9C	109.5
C4—C3—H3B	109.1	O4—C10—H10A	109.5
H3A—C3—H3B	107.8	O4—C10—H10B	109.5
C8—O4—C10	115.9 (2)	H10A—C10—H10B	109.5
C5—C4—C3	110.8 (2)	O4—C10—H10C	109.5
C5—C4—H4A	109.5	H10A—C10—H10C	109.5
C3—C4—H4A	109.5	H10B—C10—H10C	109.5
C5—C4—H4B	109.5	C12—C11—O5	106.7 (3)
C3—C4—H4B	109.5	C12—C11—H11A	110.4
H4A—C4—H4B	108.1	O5—C11—H11A	110.4
C11—O5—C1	107.9 (2)	C12—C11—H11B	110.4
C4—C5—C6	111.6 (2)	O5—C11—H11B	110.4
C4—C5—H5A	109.3	H11A—C11—H11B	108.6
C6—C5—H5A	109.3	C11—C12—O6	106.0 (3)
C4—C5—H5B	109.3	C11—C12—H12A	110.5
C6—C5—H5B	109.3	O6—C12—H12A	110.5
H5A—C5—H5B	108.0	C11—C12—H12B	110.5
C1—O6—C12	106.2 (2)	O6—C12—H12B	110.5
C8—C6—C1	113.1 (2)	H12A—C12—H12B	108.7