Diastereoselective allylation and crotylation reactions of aldehydes with potassium allyl- and crotyltrifluoroborates under Lewis acid catalysis

摘要

Potassium allyl- and crotyltrifluoroborates react with aldehydes in a process catalyzed by a variety of Lewis acids, to give the corresponding homoallylic alcohols. Of the Lewis acids examined, BF3. OEt2, used either stoichiometrically or catalytically, was found to most efficiently catalyze this reaction. The air and moisture stable potassium organotrifluoroborate salts react with a variety of alkyl, alpha- or beta- substituted alkyl, and aryl aldehydes, and lead to the adducts in high yield and with high diastereoselectivity. [References: 50]