A radical-mediated 1,3,4-trifunctionalization cascade of 1,3-enynes with sulfinates and tert-butyl nitrite: facile access to sulfonyl isoxazoles

Abstract

An unprecedented indium-promoted three-component 1,3,4-trifunctionalization cascade of 1,3-enynes with sodium sulfinates and tert-butyl nitrite (TBN) to access 5-sulfonylisoxazoles via [3+2] annulation is reported. By employing TBN as both the radical initiator and the N–O two atom unit, this method enables the formation of three new carbon–heteroatom bonds, C–S, C–N and C–O bonds, in a single reaction through a sequence of sulfonylation, isomerization, nitration and annulation with a broad substrate scope, excellent selectivity and the potential of late-stage functionalization of natural products.