Organoyttrium-Catalyzed Sequential Cyclization/Silylation Reactions of Nitrogen-Heteroaromatic Dienes Demonstrating “Aryl-Directed” Regioselectivity
作者:Gary A. Molander、Monika H. Schmitt
DOI:10.1021/jo0000527
日期:2000.6.1
The reaction of 1-allyl-2-vinyl-1H-pyrroles and 1-allyl-2-vinyl-1H-indoles with arylsilanes in the presence of catalytic [Cp(TMS)(2)Y(&mgr;-Me)](2) leads to highly selective cyclization/silylation events. In this process the active catalyst for the reaction, "Cp(TMS)(2)YH", undergoes initial olefin insertion at the vinyl group. Even isopropenyl substituents on the heteroaromatics react in preference
在催化[Cp(TMS)(2)Y(&mgr; -Me)]存在下,1-烯丙基-2-乙烯基-1H-吡咯和1-烯丙基-2-乙烯基-1H-吲哚与芳基硅烷的反应2)导致高度选择性的环化/硅烷化事件。在该方法中,用于反应的活性催化剂“ Cp(TMS)(2)YH”在乙烯基上进行初始烯烃插入。甚至杂芳族基团上的异丙烯基取代基也优先与空间上较弱的烯丙基反应。此外,观察到的区域选择性反映了“芳基导向的”过程,由此最初产生了更高取代度的仲或叔有机金属。将该中间体环化到剩余的烯烃上,随后通过sigma键易位反应进行甲硅烷基化,提供了观察到的产物。