Alkylation of vinyl sulfones as a route to 2-alkylidene tetrahydrofurans

Abstract Deprotonation of the vinyl sulfone ( 2 ) with n -butyllithium and treatment of the resulting organolithium intermediate with an alkyl halide in the presence of hexamethylphosphoramide (HMPA) gives monoalkylated adducts in 14 to 61% yields. In general, excellent regioselectivity for alkylation α to the sulfone is observed.