Reaction of α,β-unsaturated and α-phenyl acetals with epoxides, promoted by lithium-potassium mixed base LICKOR: Synthesis of homoallyl alcohols

Article abstract of DOI:10.1016/0040-4020(95)00969-8

Acetals 1, 7 and 8, in the presence of the mixed metal base LICKOR, undergo deprotonation and elimination reactions, affording enol ethers intermediates. Further hydrogen-metal exchange at the α-vinyl site of elimination products gives α-metalated species that yield, by reaction with epoxides, homoallyl alcohols. Experimental procedures are given for the conversion of the unsaturated species into the corresponding carbonyl compounds. α-substituted ethoxy diene 4 is also a useful intermediate for a one-pot synthesis of 2,6-disubstituted tetrahydro-4H-pyran-4-one 19.