Regio- and stereo-selective formation of methylenecyclopropane complexes from allenes and benzylidenepentacarbonyl tungsten

Abstract

Benzylidenepentacarbonyl tungsten reacts with dimethylallene and phenylallene, respectively, by regiospecific and stereoselective transfer of the benzylidene group to the allene and co-ordination of the product methylenecyclopropane which can be cleaved almost quantitatively from the metal by Br^–; the structure of the 2-phenyl-3,3-dimethylmethylenecyclopropane complex is established by an X-ray structure analysis.