Addition of polyfunctional and pure (E or Z) alkenylcopper and arylcopper compounds to alkylidenemalonates

Abstract

Polyfunctional and stereochemically pure (E) or (Z) alkenylcopper reagents have been generated by carbocupration of terminal alkynes or by an iodine–lithium exchange reaction and have been found to add to various diethyl alkylidenemalonates, affording γ,δ-unsaturated esters in excellent yields.