Selective Functionalization of Benzene Ring via Carbene Initiated [4,5]‐Rearrangement

The extreme similarity in electronic and steric reactivity among the C‐H bonds present on alkyl‐substituted aromatic rings presents a formidable challenge when it comes to achieving high selectivity during the para‐selective functionalization of these bonds. This article presents a unique study that delves into the para‐selective functionalization or dearomatization functionalization of benzene rings, achieved through the reaction of carbenes with allyl sulfoxides. Mechanistic investigations suggest that the transformation likely proceeds via an uncommon carbene‐mediated [4,5]‐rearrangement process.