title: Transition metal-catalyzed intermolecular [5+2] and [5+2+1] cycloadditions of allenes and vinylcyclopropanes.
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.
authors.affiliation: Departments of Chemistry and Molecular Pharmacology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Hermann A
authors.initials: HA
authors.lastname: Wegner
authors.forename: Armin
authors.initials: A
authors.lastname: de Meijere
authors.forename: Paul A
authors.initials: PA
authors.lastname: Wender