Diastereoselective approach to 11-aryl steroid skeletons through a cobalt (I)-mediated [2+ 2+ 2] cyclization of allenediynes

M Petit, C Aubert, M Malacria

Index: Petit, Marc; Aubert, Corinne; Malacria, Max Tetrahedron, 2006 , vol. 62, # 45 p. 10582 - 10593

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Citation Number: 28

Abstract

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 at C3. By designing an allenediyne ...