First Example of a Total Axial to Centered Chirality Transfer in the [2 + 2 + 2] Cycloadditions of Allenediynes

Abstract

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.