Web Release Date: April 14,
Transition Metal-Catalyzed Intermolecular [5+2] and [5+2+1] Cycloadditions of Allenes and Vinylcyclopropanes
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Departments of Chemistry and Molecular Pharmacology, Stanford University, Stanford, California 94305, and Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany
Received October 18, 2004
Abstract:
Initial examples of the intermolecular Rh(I)-catalyzed [5+2] cycloaddition reaction of bifunctional allenes and vinylcyclopropanes are described. The reactions proceed with facility and in yields of up to 99% with a variety of alkyne-, ester-, styrene-, or cyano-substituents on the allene to afford the corresponding cycloadducts. In the presence of CO, the reaction proceeds to an eight-membered ring cycloadduct and its transannularly closed product, providing the first example of a three-component [5+2+1] cycloaddition with allenes.
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