(1S*,2R*,3S*,4R*,5R*)-5-Tetra­decyloxy­methyl-7-oxabicyclo­[2.2.1]heptane-2,3-dicarb­oxy­lic anhydride

Colin N Kelly; Sarah M Sulon; Lam N Pham; Kang Rui Xiang; Richard E Sykora; David C Forbes

doi:10.1107/S1600536812046259

. 2012 Nov 17;68(Pt 12):o3374. doi: 10.1107/S1600536812046259

(1S,2R,3S,4R,5R*)-5-Tetradecyloxymethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride

Colin N Kelly ^a, Sarah M Sulon ^b, Lam N Pham ^c, Kang Rui Xiang ^c, Richard E Sykora ^c, David C Forbes ^c,^*

PMCID: PMC3588970 PMID: 23476206

Abstract

In the title compound, C₂₃H₃₈O₅, the oxabicyclo[2.2.1]heptane-2,3-dicarboxylic anhydride unit has a normal geometry and the tetradecoxymethyl side chain is fully extended. In the crystal, molecules are linked head-to-head by C—H⋯O hydrogen bonds, forming two-dimensional networks propagating along the a and c-axis directions.

Related literature

Olefinic hydrogenation of an oxabicyclo[2.2.1]hept-5-ene derivative using catalytic quantities of 10% Pd on carbon as catalyst afforded the title compound. For reviews on the Diels–Alder reaction, see: Oppolzer (1991 ▶); Pindur et al. (1993 ▶). For a review on asymmetric cycloaddion processes, see: Pellissier (2012 ▶). For a review on catalytic hydrogenations, see: Brieger & Nestrick (1974 ▶). For a review on asymmetric catalytic hydrogenation processes, see: Knowles (2002 ▶). For discussions on reaction mechanisms with specifics on kinetic and thermodynamic control, see: Lowry & Richardson (1987 ▶); Smith (2012 ▶). For a discussion on Diels–Alder selectivity using maleic anhydride, see: Palmer (2004 ▶). graphic file with name e-68-o3374-scheme1.jpg

Experimental

Crystal data

C₂₃H₃₈O₅
M _r = 394.53
Monoclinic,
a = 6.8541 (5) Å
b = 35.206 (4) Å
c = 9.2992 (7) Å
β = 99.060 (7)°
V = 2216.0 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 180 K
0.47 × 0.17 × 0.02 mm

Data collection

Agilent Xcalibur Eos diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012 ▶) T _min = 0.865, T _max = 1.000
9120 measured reflections
4053 independent reflections
2974 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.108
S = 1.04
4053 reflections
255 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2012 ▶); 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: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Click here for additional data file.^{(25.3KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812046259/zl2516sup1.cif

e-68-o3374-sup1.cif^{(25.3KB, cif)}

Click here for additional data file.^{(200KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812046259/zl2516Isup2.hkl

e-68-o3374-Isup2.hkl^{(200KB, hkl)}

Click here for additional data file.^{(9.1KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536812046259/zl2516Isup3.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯O1ⁱ	1.00	2.30	3.163 (2)	144
C4—H4⋯O2ⁱⁱ	1.00	2.44	3.377 (2)	156

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors gratefully acknowledge the National Science Foundation (NSF–CAREER grant to RES, CHE-0846680; NSF–RUI grant to DCF, CHE-0957482). DCF also gratefully acknowledges the Camille and Henry Dreyfus Foundation (TH-06–008) for partial support of this work.

supplementary crystallographic information

Comment

The pericyclic [4 + 2] cycloaddition can arguably be considered as one of the most versatile transformations when considering both atom economy and stereochemistry as reported by Oppolzer (1991), Pindur et al. (1993), and Pellissier (2012). When coupled to processes which are driven under kinetic or thermodynamic reaction conditions as illustrated by Lowry & Richardson (1987) and Smith (2012), the opportunity to illustrate both modalities on one unified system exists. That is, the irreversible hydrogenation of alkenes as reported by Brieger & Nestrick (1974) and Knowles (2002) and the reversible [4 + 2] cycloaddition when using not cyclopentadiene but furan with maleic anhydride as reported by Palmer (2004) provided us with a platform to illustrate both processes on one system. Upon reversible cycloaddition of a substituted furan with maleic anhydride, the resulting alkene was subjected to catalytic hydrogenation of the alkene.

As the end product was both crystalline and suitable for X-ray analysis, we succeeded in illustrating both reaction pathways of kinetic and thermodynamic driven processes through the establishment of five contiguous stereocenters, as shown in Fig. 1.

The title compound was isolated as the major product in moderate yield and offered definitive evidence of the facial selectivity involved in the catalytic hydrogenation as well as the juxtaposition of the anhydride relative to the bicyclic scaffold as a result of the [4 + 2] cycloaddition. The configurations of the preexisting sites C1, C2, C3, and C4 prior to the hydrogenation of the alkene are S, R, S, and R for one of the enantiomers of the racemic mixture, and R, S, R, and S for the other, respectively. The configuration of the newly formed stereocenter upon hydrogenation of the chiral racemic mixture is R for the former, S for the latter, which confirms a profile of kinetic reaction control for the hydrogenation and thermodynamic reaction control for the cycloaddition.

In the solid state structure of the title compound (Fig. 1) the small amount of vibrational motion of the tetradecoxymethyl tail group indicates a significant degree of non-covalent interactions within those domains. No unusual deviations from normal bond distances or bond angles are observed in the title molecule.

In the crystal, molecules are linked head-to-head via C-H···O hydrogen bonds (Table 1) to form V-shaped or folded two-dimensional networks extending in the a and c directions. In the crystal, there are clear hydrophobic and hydrophilic domains (Fig. 2).

Experimental

The Diels-Alder adduct, 5-tetradecoxymethyl-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, was first synthesized by the following method. To a solution of 3-tetradecoxymethylfuran (1.3 g, 4.5 mmol) in toluene (25 ml) was added maleic anhydride (0.56 g, 5.7 mmol). The reaction mixture was allowed to stir at room temperature for a period of 24 h at which time the reaction was determined complete by thin layer chromatography. The reaction mixture was concentrated under reduced pressure and purified by column chromatography (EtOAc/hexanes, 1/4), to afford the cyclo adduct. (737 mg, 42% yield). TLC R_f 0.31 (EtOAc/hexanes, 1/4). Spectroscopic data for the Diels-Alder adduct, 5-tetradecoxymethyl-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, are available in the archived CIF.

The title compound was prepared by bubbling hydrogen gas into a tetrahydrofuran (50 ml) solution consisting of the Diels-Alder adduct starting material (607 mg, 1.5 mmol) and 10% Pd/C (64 mg) for a period of no less than 90 min. at room temperature. The reaction mixture was then filtered through a plug of Celite and concentrated under reduced pressure. Purification by column chromatography (EtOAc/hexanes, 1/4) afforded the title compound (154 mg, 26% yield). Colourless plate-like crystals were obtained on slow evaporation of a solution in the solvent mixture EtOAc/hexanes (1/4). Spectroscopic data for the title compound are available in the archived CIF.