Ligand effect of bulky 2,2-dialkyl-1-phosphaethenes on Au-catalyzed cycloisomerization of 1,6-enynes and lactonization of pent-4-ynoic acids

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• 作者：Shigekazu Ito ; Shuhei Kusano ; Noboru Morita ; Koichi Mikami ; Masaaki Yoshifuji
• 关键词：Phosphaalkenes ; Gold catalysts ; Enyne cyclization ; Steric protection ; γ ; -Lactones
• 刊名：Journal of Organometallic Chemistry
• 出版年：2010
• 出版时间：15 January 2010
• 年：2010
• 卷：695
• 期：2
• 页码：291-296
• 全文大小：541 K

文摘

2,2-Dimethyl- and 2-benzyl-2-methyl-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaethenes were employed as ligand of mononuclear chlorogold(I) complexes, which catalyzed cycloisomerization of 1,6-enyne affording vinylcyclopentene exclusively in the absence of silver co-catalyst. The reaction mechanisms are discussed based on DFT calculations. In addition to the cycloisomerization, the phosphaalkene–chlorogold(I) complexes catalyzed cyclization of pent-4-ynoic acids providing γ-methylene-γ-lactones under basic conditions.