Chemoselective carbene insertion into the N−H bonds of NH3·H2O
Zhaohong Liu, Yong Yang, Qingmin Song, Linxuan Li, Giuseppe Zanoni, Shaopeng Liu, Meng Xiang, Edward A. Anderson, Xihe Bi
Abstract
Abstract The conversion of inexpensive aqueous ammonia (NH 3 ·H 2 O) into value-added primary amines by N−H insertion persists as a longstanding challenge in chemistry because of the tendency of Lewis basic ammonia (NH 3 ) to bind and inhibit metal catalysts. Herein, we report a chemoselective carbene N−H insertion of NH 3 ·H 2 O using a Tp Br3 Ag-catalyzed two-phase system. Coordination by a homoscorpionate Tp Br3 ligand renders silver compatible with NH 3 and H 2 O and enables the generation of electrophilic silver carbene. Water promotes subsequent [1,2]-proton shift to generate N−H insertion products with high chemoselectivity. The result of the reaction is the coupling of an inorganic nitrogen source with either diazo compounds or N- triftosylhydrazones to produce useful primary amines. Further investigations elucidate the reaction mechanism and the origin of chemoselectivity.