Synthesis of gem‐Difluorocyclobutane‐Fused Indolines via Ruthenium‐Catalyzed Defluorinative Annulation of Trifluoromethyl Carbenoids with 2‐Alkenylanilines

Abstract

AbstractA ruthenium‐catalyzed defluorinative annulation of 2‐alkenylanilines with α‐trifluoromethyl diazoester or diazoketones is described. The reaction has broad substrate scope, affording a range of gem‐difluorocyclobutane‐fused indolines in moderate to good yields with cis‐configuration. Mechanistic investigations indicate that the reaction proceeds through a sequential N−H insertion/C−F bond cleavage/[2+2] cycloadditon process. α‐Trifluoromethyl‐α‐diazo reagents serve as gem‐difluorinated C2 subunits by cleaving one C−F bond.