Mechanistic Study of Indolizine Heterocycle Formation by Ruthenium(II)-Assisted Three-Component Cross-Coupling/Cyclization

详细信息    查看全文

• 作者：Chunhong Zhang ; Hong Zhang ; Laiying Zhang ; Ting Bin Wen ; Xumin He ; Haiping Xia
• 刊名：Organometallics
• 出版年：2013
• 出版时间：July 8, 2013
• 年：2013
• 卷：32
• 期：13
• 页码：3738-3743
• 全文大小：329K
• 年卷期：v.32,no.13(July 8, 2013)
• ISSN：1520-6041

文摘

In the presence of the acid HBF₄, 3-alkenyl-2-phosphonium indolizines 3a鈥?b>c can be produced respectively by adding PhC鈮COCH₃ (2a), CH₃OCOC鈮COOCH₃ (2b), and CH₃CH₂C鈮COCH₃ (2c) to a mixture of ruthenium complex RuCl₂(PPh₃)₃ and the propargyl alcohol (2-Py)CH(OH)C鈮H (1). We carefully investigated the mechanism of this reaction by means of structurally characterizing two key intermediates, ruthenium vinyl (4) and ruthenium carbene (5), and by deuterium-labeling experiments. A plausible mechanism is proposed, which involves addition of a proton to an alkyne carbon and the insertion of an alkyne into the C伪 bond of an alkenylcarbene group, followed by an 伪-H elimination and reductive elimination.