Diastereoselective approach to 11-aryl steroid skeletons through a cobalt(I)-mediated [2+2+2] cyclization of allenediynes
作者:Marc Petit、Corinne Aubert、Max Malacria
DOI:10.1016/j.tet.2006.05.091
日期:2006.11
The cobalt(I)-mediated [2+2+2] cycloaddition reactions of allenediynes of yne-allene-yne type bearing an aryl group on the allene are described. The cyclizations are totally chemo- and regioselective and show low diastereoselectivities. η4-Complexed tricyclic (6,6,6) compounds were obtained in good yields as mixtures of endo/exo diastereomers. The cyclization is also compatible with an oxyfunctionality
描述了钴(I)介导的在烯丙基上带有芳基的炔基-炔烃-炔类型的烯丙炔的[2 + 2 + 2]环加成反应。环化是完全化学和区域选择性的,并且显示出低的非对映选择性。η 4 -Complexed三环以良好产率得到作为混合物(6,6,6-)化合物内切/外切非对映体。环化也与C3处的氧官能度相容。通过设计具有预先存在的D环的烯丙二炔,我们成功地一步一步以完全非对映选择性的方式构建了11-芳基类固醇的骨架,并同时在C10处引入了角甲基并在C11处引入了芳基取代基。