Following the general procedure for the preparation of aldehydes from alkenes of Description 11, methyl (2E)(4S)-6-[(3-chloropropyl)sulfonyloxy]-5,5-dimethyl-4-(1,1,2,2-tetramethyl-1-silapropoxy)hex-2-enoate (15a) (2.4 g, 5.4 mmol) dissolved in 25 mL of dichloromethane (DCM) was treated with a mixture of oxygen and ozone (O2/O3). Upon completion of the reaction, 2 mL (1.59 g, 27.2 mmol) of dimethyl sulfide (DMS) was added. 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=1:3) as eluent to provide 1.1 g (52% yield) of the title compound (15b) as a colorless oil. Rf=0.75 (EtOAc/Hxn=1:2). 1H NMR (400 MHz, CDCl3): δ=0.07 (s, 3H), 0.10 (s, 3H), 0.96 (s, 9H), 1.06 (s, 3H), 1.09 (s, 3H), 2.30-2.37 (m, 2H), 3.28-3.32 (m, 2H), 3.69-3.73 (m, 3H), 4.01 (d, J=9.6 Hz, 1H), 4.12 (d, J=9.6 Hz, 1H), 9.62 (d, J=2.4 Hz, 1H) ppm. MS (ESI) m/z 409.13 (M+Na)+. The analytical data was consistent with the proposed structure.
