Rhodium(iii)-catalyzed successive C(sp2)–H and C(sp2)–C(sp2) bond activation of aryl oximes: synthetic and mechanistic studies

Abstract

Merging selective C–H cleavage with C–C cleavage in a tandem reaction has been a practical strategy that permits skeletal diversification from simple raw materials. Herein, we describe a rhodium(III)-catalyzed redox-neutral reaction of aryl oximes and internal alkynes to generate novel N-(2-cyanoaryl) indanone imines. The deconstruction of aryl oximes delivers nitrile-containing molecules with good yields, regioselectivities and atom economy, with the generation of water as a sole by-product. The experimental and theoretical studies afford mechanistic insights into this transformation. Selective nitrogen-directed C(sp²)–H cyclization and subsequent acetonitrile-enabled spiro-cyclization realize the effective C–C activation under mild conditions. The work achieves an attractive integration of C–H activation with C–C activation in oxime transformation.