Synthesis of differentially protected/functionalised acetylenic building blocks from p-benzoquinone and their use in the synthesis of new enediynes

Abstract

Sequential addition of two different lithium acetylides to p-benzoquinone yielded diastereomeric mixtures of 1,4-diethynylcyclohexa-2,5-diene-1,4-diols wherein the two ethynyl groups bear different protective/functional groups. Selective deprotection to the terminal acetylene followed by Pd(0) mediated coupling with Z-1,2-dichloroethene yielded new enediynes bearing cyclohexa-2,5-diene units.