A substrate-controlled Ru(ii)-catalyzed C–H activation/[5 + 2] annulation cascade and unusual acyl migration to synthesize diverse indoline scaffolds

Abstract

A substrate-controlled Ru(II)-catalyzed C–H activation/[5 + 2] annulation cascade and unusual acyl migration to synthesize diverse indoline scaffolds are reported. The most pronounced advantage is that this strategy can offer a highly selective C–H activation of N-benzamidine indoline with two reaction sites prone to C–H activation to selectively prepare a 1,7-fused indoline scaffold and a C7-alkylated/N′-acylated indoline ring by varying its diazo synthons. More importantly, the NH directing group of N-aryl benzamidines is fully utilized and atom-economically integrated into the target products with a good yield and broad substrate scope.