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Ruthenium-Catalyzed Reactions of 1-Cyclopropyl-2-propyn-1-ols with Anilines and Water via Allenylidene Intermediates:  Selective Preparation of Tri- and Tetrasubstituted Conjugated Enynes

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posted on 25.04.2007, 00:00 by Yoshihiro Yamauchi, Gen Onodera, Ken Sakata, Masahiro Yuki, Yoshihiro Miyake, Sakae Uemura, Yoshiaki Nishibayashi
Ruthenium-catalyzed efficient preparation of the conjugated enynes can be carried out in the reactions of 1-cyclopropyl-2-propyn-1-ols with nitrogen- and oxygen-centered nucleophiles such as anilines and water in the presence of a catalytic amount of sulfur-bridged diruthenium complexes. The use of such complexes as catalysts realizes the completely stereoselective preparation of tri- and tetrasubstituted conjugated enynes, where ruthenium−allenylidene complexes work as key intermediates. The direct attack of nucleophiles on a cyclopropane ring connected to an allenylidene ligand is a key step to obtain the enynes stereoselectively.