2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → HCID 86628904, compound

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Reaction Steps

Following the general procedure for the oxidative cleavage of (4-methoxy)benzyl ethers of Description 19, (ethoxycarbonyloxy)ethyl (2R)-4-[(3-chloropropyl)sulfonyloxy]-2-[(4-methoxyphenyl)methoxy]-3,3-dimethylbutanoate (36a) (0.77 g max.) dissolved in a mixture of dichloromethane (DCM) and water (10:1) (10 mL) was treated with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (0.68 g, 3.0 mmol). After work-up, the crude material was purified by silica gel column chromatography using a mixture of ethyl acetate (EtOAc) and hexane (Hxn) (EtOAc/Hxn=1:2) as eluent to provide 0.2 g (19% yield over two steps) of the title compound (36b) as a colorless oil. Rf=0.57 (EtOAc/Hxn=1:2). 1H NMR (400 MHz, CDCl3, both diastereomers): δ=0.99-1.01 (2s, 3H), 1.12-1.14 (2s, 3H), 1.32-1.37 (m, 3H), 1.59-1.62 (m, 3H), 2.31-2.38 (m, 2H), 2.89-2.94 (2d, J=6.0, 6.8 Hz, 1H), 3.31-3.35 (m, 2H), 3.69-3.72 (m, 2H), 3.97-4.02 (m, 1H), 4.06-4.08 (m, 1H), 4.10-4.22 (m, 1H), 4.21-4.28 (m, 2H), 6.83-6.89 (m, 1H) ppm. MS (ESI) m/z: 426.94 (M+H)+. The analytical data was consistent with the proposed structure.

Provenance & Evidence