Versatile cyclisation reactions using selenoboranes

Abstract

Tris(phenylseleno)borane and tris(methylseleno)borane reacted with terminal acetylenes to afford (Z)-vinyl selenides. This reaction was initiated by oxygen and the intermediates were vinyl radicals. This radical reaction could be applied to the intramolecular free radical cyclisation of enynes and some heterocycles and carbocycles were synthesised. This novel method could be also employed in the synthesis of α-kainoid derivatives.