Cyclization of Nonterminal Alkynic β-Keto Esters Catalyzed by Gold(I) Complex with a Semihollow, End-Capped Triethynylphosphine Ligand
Cyclization of Nonterminal Alkynic β-Keto Esters Catalyzed by Gold(I) Complex with a Semihollow, End-Capped Triethynylphosphine Ligand
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DOI：
10.1021/ol802079r
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发表时间：
2008-11-06
期刊：
影响因子：
5.2
通讯作者：
Sawamura, Masaya
中科院分区：
文献类型：
--
作者：
Ito, Hideto;Makida, Yusuke;Sawamura, Masaya
一种阳离子金（I）配合物与一种半空心形状的三炔基膦催化各种内炔基β-酮酯的5-exo-dig和6-endo-dig环化反应，在反应速率和产物产率方面显示出明显优于金（I）-PPh 3配合物。有人提出，在催化口袋中的金绑定炔基必须有点折叠，这样的空间效应使得熵更有利的碳-碳键的形成。
A cationic gold(l) complex with a semihollow-shaped trialkynylphosphine catalyzed 5-exo-dig and 6-endo-dig cyclizations of various internal alkynic beta-keto esters, showing a marked advantage over a gold(I)-PPh3 complex with respect to the rates of the reactions and the product yields. It is proposed that the gold-bound alkynic substrate in a catalytic pocket must be somewhat folded and that such a steric effect makes the carbon-carbon bond formation entropically more favorable.