preparation of substitutedlinearenediyneesters bearing the double bond either at the terminal or at internal position and the ester substituent either at the alkyne or at the alkene terminus is presented. Their cobalt(I)-mediated [2+2+2] cyclizations produce the η4-complexed tricyclic compounds in very good yields. The endo/exo selectivity depends on the position of the ester in the enediyne, but the
First Example of a Total Axial to Centered Chirality Transfer in the [2 + 2 + 2] Cycloadditions of Allenediynes
作者:Olivier Buisine、Corinne Aubert、Max Malacria
DOI:10.1055/s-2000-6300
日期:——
The cobalt-mediated [2 + 2 + 2] cycloaddition of allenediynes bearing a phosphine oxide group at one alkyne terminus is a completely regio-, chemo- and diastereoselective high yielding process. Moreover, a total transfer of chiral information from axial to centered chirality is evident, which makes this reaction a new and powerful tool for the preparation of enantiomerically enriched tricyclic derivatives.