Diverging Pathways in the Activation of Allenes with Lewis Acids and Bases: Addition, 1,2-Carboboration, and Cyclization

详细信息    查看全文

• 作者：Rebecca L. Melen ; Lewis C. Wilkins ; Benson M. Kariuki ; Hubert Wadepohl ; Lutz H. Gade ; A. Stephen K. Hashmi ; Douglas W. Stephan ; Max M. Hansmann
• 刊名：Organometallics
• 出版年：2015
• 出版时间：August 24, 2015
• 年：2015
• 卷：34
• 期：16
• 页码：4127-4137
• 全文大小：613K
• ISSN：1520-6041

文摘

The reactions of allenes with frustrated (or cooperative) Lewis acid/base pairs result in the 1,4-addition of the base pair to the allene. The reactions of allenyl ketones and esters just in the presence of the strong Lewis acid B(C₆F₅)₃ afford the selective formation of the 1,2-carboboration products. In both cases the Lewis acid activates the allene to either a C₆F₅ migration or nucleophilic attack by the Lewis base. In addition to the 1,2-carboboration pathway, which can be viewed as being triggered by activation of the ketone (蟽-activation), in the case of allenyl esters the corresponding cyclization products are observed in the presence of water.