Yan M, Jin T, * Ishikawa Y, Minato T, Fujita T, Chen L.-Y, Bao M, Asao N, Chen M.-W,
Yamamoto Y. Tohoku University, Sendai, Japan and Dalian University of Technology,
P. R of China
Nanoporous Gold Catalyst for Highly Selective Semihydrogenation of Alkynes: Remarkable
Effect of Amine Additives.
J. Am. Chem. Soc. 2012;
134: 17536-17542
Key words
nanoporous gold - semihydrogenation - alkynes - amines
Significance
A nanoporous gold catalyst (AuNPore), which was prepared by dealloying a homogeneous
Au30Ag70 alloy in nitric acid (70 wt%), catalyzed the semihydrogenation of alkynes with organosilanes
and water as the hydrogen source to afford the corresponding alkenes. The reaction
of phenylacetylene with PhMe2SiH and water in DMF proceeded in the presence of 2 mol% of AuNPore to give styrene
as the sole product (method A: 35 °C, 3 h, 96% yield).
1-Dodecyne underwent the semihydrogenation efficiently in acetonitrile with 50 mol%
of pyridine (method B: 80 °C, 8 h, 98% yield).
Comment
The catalytic ability of various catalysts was examined for the semihydrogenation
of phenylacetylene: AuNPore (96%), AuCl (18%), Au30Ag70 alloy (0%), PdNPore (54%), and Pd/C (20%). The authors proposed the reaction pathway
including the generation of the H– on the AuNPore surface ([AuNPore-H]–) and pyridinium cation ([HPy]+) which subsequently react with the alkynes to form the corresponding Z-alkenes.
