Silylstannylation of Allenes and Silylstannylation−Cyclization of Allenynes. Synthesis of Highly Functionalized Allylstannanes and Carbocyclic and Heterocyclic Compounds
作者:Ramaiah Kumareswaran、Seunghoon Shin、Isabelle Gallou、T. V. RajanBabu
DOI:10.1021/jo049010z
日期:2004.10.1
silicon−tin reagents to undergo the cyclization illustrate the scope and limitations of the reaction. Based on the isolation of intermediates, a mechanism for the formation of the cyclic compounds is proposed. Model transition states to explain the stereoselectivity in cyclization of substituted allenynes are provided. Further elaboration using the vinyltin and vinylsilane moieties should lead to highly functionalized
通过Pd催化(0),trialkylsilyltrialkylstannane(R 3 Si的SNR” 3)的试剂进行高度选择性添加到1,2-二烯-7-炔和1,2-二烯8 -炔,得到2- vinylalkylidenecyclopentanes有硅和双键上的锡取代基。二萘烷和硼烷锡的类似添加表明,与甲硅烷基锡的反应在处理双功能试剂的容易性和反应后产物的分离方面是优异的。化学和区域选择性由丙二烯单元增强的反应性控制,而(Z环苯乙烯基亚乙烯基的-(-)-几何形状是顺式碳共金属化和随后从Pd上的还原消除,并保留了乙烯基碳上的构型的结果。高度官能化的吡咯烷和吲哚唑烷的合成以及某些类型的烯丙炔和硅锡试剂不愿进行环化反应说明了反应的范围和局限性。基于中间体的分离,提出了形成环状化合物的机理。提供了模型过渡态以解释取代的烯丙炔环化中的立体选择性。使用乙烯基锡和乙烯基硅烷部分的进一步加工将导致高度官能化的