Nitrogen Acyclic Gold(I) Carbenes: Excellent and Easily Accessible Catalysts in Reactions of 1,6-Enynes

Abstract

Complexes [AuCl{C(NHR)(NHR 0 )}] and [AuCl{C(NHR)(NEt 2 )}] (R= t Bu, p-Tol, Xylyl, p-C 6 H 4 -COOH, p-C 6 H 4 COOEt, R 0 = Me, n Bu, i Pr, n heptyl, 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.

Mechanistic insights and functionalization of alkynes in homogeneous gold catalysis.

“…In the cycloisomerization of enyne (Figure 22), [170][171][172] we observed a similar effect as in previous reactions. We chose this reaction because cycloisomerizations of enynes have emerged as attractive tools for the synthesis of various types of cyclic compounds in an easy one-pot process in which a wide range of transition metal complexes can be used, either in a catalytic or stoichiometric manner.…”

New and Easily Accessible Nitrogen Acyclic Gold(I) Carbenes: Structure and Application in the Gold‐Catalyzed Phenol Synthesis as well as the Hydration of Alkynes

“…While writing this manuscript, a publication by Echavarren, Espinet et al [17] addressing the same subject was published as an electronic asap paper. Fortunately, only two NAC complexes are identical in that publication and our work and different applications in catalysis have been investigated.…”

Gold Functionalized Platinum M12L24‐Nanospheres and Their Application in Cyclization Reactions

“…[32][33][34] Theg old catalysts inside the sphere rapidly converted 9 into the 5-membered product (12)a s the major compound (Table 5, entry 1). In addition, small amounts of the six-membered ring 10 and hydrolyzed product (13)a re also formed.…”