Metal-free oxidative [2+2+1] heteroannulation of 1,7-enynes with thiocyanates toward thieno[3,4-c]quinolin-4(5H)-ones

Abstract

A new metal-free oxidative [2+2+1] heteroannulation of 1,7-enynes with thiocyanates for producing thieno[3,4-c]quinolin-4(5H)-ones is presented. This reaction employs benzoylperoxide (BPO) as the oxidant and sodium thiocyanate as the sulfur source to enable the formation of three chemical bonds, two C–S bonds and one C–C bond, in a single reaction, and represents a new, practical access to S-heterocycles with the avoidance of the use of metal catalysts and excess bases.