C(Cl)(=O)C(Cl)=O.CS(C)=O.[Si:11]([O:18][C@H:19]1[CH2:24][CH2:23][C@H:22](/[CH:25]=[C:26](\[CH3:29])/[CH2:27][OH:28])[CH2:21][CH2:20]1)([C:14]([CH3:17])([CH3:16])[CH3:15])([CH3:13])[CH3:12].C(N(CC)CC)C>C(Cl)Cl>[Si:11]([O:18][C@H:19]1[CH2:20][CH2:21][C@H:22](/[CH:25]=[C:26](\[CH3:29])/[CH:27]=[O:28])[CH2:23][CH2:24]1)([C:14]([CH3:17])([CH3:16])[CH3:15])([CH3:13])[CH3:12]To a -78° C. solution of oxalyl chloride (105 μL, 1.2 mmol) in 1.0 mL of methylene chloride was added dimethylsulfoxide (170 μL, 2.4 mmol). The resulting solution was stirred for 5 min and then 170 mg (0.6 mmol) of the alcohol 135 was added in 1.0 mL of methylene chloride. The reaction mixture was stirred at -78° C. for 45 min at which time 500 μL (3.6 mmol) of triethylamine was added and the solution was allowed to warm to ambient temperature. The reaction was quenched with 1.0N HCl and the aqueous layer was extracted with three portions of methylene chloride. The combined organic extracts were dried over MgSO4 and evaporated to dryness to give the crude aldehyde 136 which was used directly in the next reaction. 1H NMR consistent with structure.
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