Key Laboratory of Organic Synthesis of Jiangsu Province, Department of Chemistry and Chemical Engineering, Soochow University, Suzhou 215006, China.
Org Lett. 2010 Dec 3;12(23):5538-41. doi: 10.1021/ol1024794. Epub 2010 Nov 11.
A mechanism of the Au-catalyzed cycloisomerization of propargylpyridines has been investigated. Both DFT computational and experimental results strongly support generation of a Au-carbene via a cyclization/proton transfer sequence over the previously proposed path involving a Au-vinylidene intermediate. For the β-Si-substituted Au-carbene (G = SiR(3)), a 1,2-Si migration was shown to be kinetically favored over a 1,2-H shift. This study highlights the importance of alternative pathways that could explain reactivities commonly attributed to an alkyne-vinylidene isomerization in Au catalysis.
已研究了 Au 催化炔丙基吡啶环异构化的机理。DFT 计算和实验结果均强烈支持通过环化/质子转移序列生成 Au-卡宾,而不是之前提出的涉及 Au-亚乙烯基中间体的途径。对于β-Si 取代的 Au-卡宾(G = SiR(3)),表明 1,2-Si 迁移比 1,2-H 迁移具有动力学优势。这项研究强调了替代途径的重要性,这些途径可以解释通常归因于 Au 催化中的炔基-亚乙烯基异构化的反应性。