Highly efficient mesoporous polymer supported phosphine-gold(i) complex catalysts for amination of allylic alcohols and intramolecular cyclization reactions

Abstract

A series of novel heterogeneous gold(i) catalysts were synthesized by immobilizing gold(i) complexes on ordered mesoporous polymer FDU-15 and characterized by XRD, N₂ adsorption-desorption, FT-IR, TEM, EDS, etc. The catalytic activities of these catalysts were evaluated by the amination reactions of allylic alcohols. Among the catalysts investigated, FDU-(p-CF₃Ph)₂PAuCl (3d) was identified as the most efficient catalyst. Compared to the homogeneous catalyst, the enhanced catalytic activity of the heterogeneous gold(i) catalyst is closely related to the mesoporous structure of FDU-15. The catalytic system was suitable for a broad range of substrates and can be easily recovered and recycled at least twelve times without significant loss of catalytic activity. In addition, the catalytic performance of 3d was further examined for intramolecular cyclization for the synthesis of heterocyclic compounds.

Scheme 1. The strategy for the synthesis FDU-type mesopolymer supported gold(i) catalysts 3a–3d.

Fig. 1. Powder XRD patterns of (a) FDU-15, (b) 1, (c) 2d and (d) 3d.

Fig. 2. The nitrogen adsorption–desorption isotherms and BJH pore size distribution curves of FDU-15, 1, 2d and 3d.

Fig. 3. TEM images of (a) FDU-15, (b) 1 (FDU-CH₂Cl), (c) 2d and (d) 3d.

Fig. 4. The reusability of sample 3d in the amination reaction of trans-1,3-diphenyl-2-propen-1-ol with p-toluenesulfonamide.

Scheme 2. The intramolecular cyclization of 9 to 10.