Preparation of polymer incarcerated gold nanocluster catalysts (PI-Au) and their application to aerobic oxidation reactions of boronic acids, alcohols, and silyl enol ethers

TETRAHEDRON

卷:70

Article

Miyamura, Hiroyuki¹  Yasukawa, Tomohiro¹  Kobayashi, Shu¹ 

[1] Univ Tokyo, Sch Sci, Dept Chem, Bunkyo Ku, Tokyo 1130033, Japan

关键词: Gold nanocluster;    Polystyrene;    Heterogeneous catalyst;    Aerobic oxidation;    Silyl enol ether;   

DOI  :  10.1016/j.tet.2014.05.014

来源: Elsevier

【 摘 要 】

Heterogeneous gold nanocluster catalysts immobilized by the method known as polymer incarceration were prepared. Polystyrene-derived polymers with epoxide and alcohol moieties, which could be cross-linked under heating conditions, were employed as supports for their preparation. Cationic gold salts were reduced in a solution of NaBH4 and the polymers. Poor solvents for the polymers were added, and the polymers were precipitated and encapsulated gold nanoclusters with weak but multiple interactions between a gold nanocluster surface and the pi electrons of benzene rings. The polymer capsules were heated under neat conditions to afford heterogeneous gold nanocluster catalysts; namely, polymer incarcerated gold nanoclusters. The catalysts thus prepared could be applied to the aerobic oxidation of phenyl boronic acids, alcohols, and silyl enol ethers. We found that the choice of polymers, good and poor solvents for the polymers, metal loadings, heating conditions for cross-linking, and final activation were all crucial for obtaining high-activity catalysts. (C) 2014 Elsevier Ltd. All rights reserved.

【 授权许可】

Free