Synthesis of activated spirocyclopentanes via a cascade Michael/alkylation reaction of ethyl-4-chloro-3-oxobutanoate and 2-arylidene-1,3-indandiones

Abstract

A cascade Michael/alkylation reaction of ethyl-4-chloro-3-oxobutanoate and 2-Arylidene-1,3-indandiones had been studied, providing a number of activated spirocyclopentanes in excellent yields (up to 96%) and diastereoselectivities (up to dr > 20:1). Different bases were evaluated and triethylamine was found to be the most efficient for this transformation under mild reaction.