Dimethyl Sulfoxide → 3-[[(1,1-Dimethylethyl)dimethylsilyl]oxy]tetrahydro-4-methoxy-5-methyl-2H-pyran-2-carboxaldehyde

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Reaction Steps

Into a stirred solution of oxalylchloride (0.07 ml, 0.81 mmol) in dry dichloromethane (3 ml) was dropped a solution of dry dimethylsulfoxide (0.11 ml, 1.49 mmol) in dry dichloromethane at -60° C. and stirring was continued at this temperature (-60° C.) for 15 minutes. Then a solution of the title compound of Example 39 (180 mg, 0.62 mmol) in dry dichloromethane (1 ml) was added slowly. After being stirred for additional 15 minutes at -60° C. triethylamine (0.43 ml, 3.1 mmol) was added slowly, the mixture was stirred for 10 minutes at -60° C. and then allowed to come to ambient temperature and stirred for 40 minutes at this temperature. The solvent was removed on a rotary evaporator, and the residue was partitionated between ether and ice-water. The organic phase was separated, dried over sodium sulfate and evaporated in vacuo to leave an oil (157 mg) which was chromatographed on silica gel eluting with ethyl acetate/petroleum ether (1:4). The relevant fractions were combined and then evaporated in vacuo to yield the desired title aldehyde as a pale yellowish oil. Yield 108 mg.

Provenance & Evidence