Tripodal S-Ligand Complexes of Copper(I) as Catalysts for Alkene Aziridination, Sulfide Sulfimidation, and C-H Amination

Abstract

Copper(I) complexes of tris(thioimidazolyl)borates (R′TmR), including [Cu(TmPh)(PR″3)] (R″ = Ph, Cu1; Cy, Cu2) and [Cu(R′TmPh)(PR″3)]+ (R′ = N-methylimidazole; R″ = Ph, Cy) were prepared and characterized by spectroscopic methods. The X-ray crystal structures of Cu1 and Cu2 feature a tripodal TmPh ligand coordinated in κ3-S,S,S mode. Using Cu2 as a catalyst (loading: 1 mol %), the aziridination of styrenes and sulfimidation of thioanisoles with PhI═NTs at RT for 3 and 0.5 h, respectively, both resulted in product yields of up to 99%. Cu2 also catalyzed intramolecular amination of the aryl C–H bond of vinyl azides with up to 98% yield. DFT calculations were performed to gain insight into the mechanism of the Cu2-catalyzed aziridination reaction.