Remote activating strategy enabled (RASE) π-bond migratory dealkylative C–N coupling utilising N-fluorobenzenesulfonimide (NFSI) as a bifunctional domino reagent

Abstract

A remote activating strategy enabled (RASE) π-bond migratory dealkylative C(sp³)–N and C(sp²)–N coupling with 2-alkoxylthiazole through C(sp³)–H and C(sp²)–H cleavage has been achieved under mild conditions, affording N-benzyl or N-phenyl thiazol-2(3H)-ones, respectively. N-Fluorobenzenesulfonimide (NFSI) serves as a crucial bifunctional domino reagent: it not only generates a nitrogen-centred radical that initiates N–C or N–N radical relay, thereby providing the electrophile coupling partner, but also produces N-hydrobenzenesulfonimide (NHSI), a key carbocation scavenger that triggers the π-bond migratory dealkylation of 2-alkoxylthiazole to yield the nucleophilic thiazol-2(3H)-one coupling partner. A plausible mechanism has been proposed based on the results of mechanistic studies.