A novel method for the synthesis of a series of silyl ethers of 3-(silyloxy)tetrahydrofuran-2-methanols bearing substituents at all four carbon atoms of the ring has been developed. The process involves first non-aldol aldol reaction of the epoxy silyl ether 8 to give the anti aldol product 9, stereoselective olefination and reduction to the ( E )- and ( Z )-allylic alcohols 10 and 11, diastereoselective epoxidation of these alcohols to give any of the four diastereomeric epoxy alcohols 12 − 15, silylation of the alcohols to give the epoxy silyl ethers 27 − 30, and final Lewis acid catalyzed rearrangement of the epoxy silyl ethers to give the desired products 31 − 33 and 36 . In the first three instances, good yields of the desired 3-(silyloxy)-2-((silyloxy)methyl)tetrahydrofurans were obtained. However, rearrangement of the epoxy silyl ether 27 gave a mixture of products, the bis-silyl ether 36 as well as the products of a second non-aldol aldol process. This hydride migration to give the 3,5-bis((trialkylsilyl)oxy)-2,4-dimethylalkanal 35 or its internally protected 1-(silyloxy)pyran 38 can be made to occur in good yield.
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Jung et al. (1997) studied this question.
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