γ-Carboline synthesis enabled by Rh(iii)-catalysed regioselective C–H annulation

Abstract

A redox-neutral Rh(III)-catalyzed C–H annulation of indolyl oximes was developed. Relying on the use of various alkynyl silanes as the terminal alkyne surrogates, the reaction exhibited a reverse regioselectivity, thus giving an exclusive and easy way for the synthesis of a wide range of substituent free γ-carbolines at C3 position with high efficiency. Deuterium-labelling experiments and kinetic analysis have preliminarily shed light on the working mode of this catalytic system.