Rhodium(I)-catalyzed [3+2] intramolecular cycloaddition of alkylidenecyclopropane-propargylic esters

An interesting rhodium(I)-catalyzed [3+2] intramolecular cycloaddition of alkylidenecyclopropanes 1 containing propargylic esters has been described in this context. A variety of bicyclo[3.3.0]octene derivatives were obtained in moderate to good yields under mild conditions. The alkylidenecyclopropane-enynes 2 could be also converted to the corresponding cycloadducts 3 in good yields. (C) 2011 Elsevier Ltd. All rights reserved.