Nitrogen acyclic gold(I) carbenes: Excellent and easily accessible catalysts in reactions of 1,6-enynes
C. Bartolomé, Z. Ramiro, D. García-Cuadrado, P. Pérez-Galán, M. Raducan, C. Bour, A. M. Echavarren, P. Espinet
Abstract: Complexes [AuCl{C(NHR)(NHR′)}] and [AuCl{C(NHR)(NEt2)}] (R = tBu, p-Tol, Xylyl, p-C6H4COOH, p-C6H4COOEt, R′ = Me, nBu, iPr, nheptyl, p-Tol) have been prepared by reaction of the corresponding isocyanogold complexes [AuCl(CNR)] with either primary amines or diethylamine. All the prepared carbenes are reactive and highly selective catalysts for skeletal rearrangement, methoxycyclization of 1,6-enynes, and other mechanistically related gold-catalyzed transformations. Overall, these easily accessible nitrogen acyclic carbene (NAC) gold complexes were not second to NHC complexes and were advantageous to obtain different products.