Morita–Baylis–Hillman‐Type [3,3]‐Rearrangement: Switching fromZ‐ toE‐Selective α‐Arylation by New Rearrangement Partners

Abstract

Abstractα‐aryl α,β‐unsaturated carbonyls represent an important class of derivatizable synthetic intermediates, however, the synthesis of such compounds still remains a challenge. Recently, we showcased a novelZ‐selective α‐arylation of α,β‐unsaturated nitriles with aryl sulfoxides via [3,3]‐rearrangement involving an Morita–Baylis–Hillman (MBH) process. Herein, we demonstrate the feasibility of reversing the stereoselectivity of such MBH‐type [3,3]‐rearrangement by switching to a new pair of rearrangement partners consisting of aryl iodanes and α,β‐unsaturated oxazolines. As a result, the two protocols complement each other in approachingE‐ orZ‐α‐aryl α,β‐unsaturated carbonyl derivatives. Mechanistic studies reveal a possible reaction pathway and provide an explanation for the opposite stereoselectivities.