VINYLCYCLOPENTANE SYNTHESIS VIA PHENYLTHIO RADICAL CATALYZED ALKENYLATION OF VINYLCYCLOPROPANES - PREPARATIVE AND MECHANISTIC STUDIES

1-Vinylcyclopropanes bearing ether or ester substituents at C(2) of the cyclopropyl ring or alkyl groups at other ring (or alkenyl) positions were subjected to PhS. catalyzed olefination with ester- or oxygen-functionalized alkenes. In some instances, variations in reaction conditions (low temperature, Lewis acids) led to levels of stereoselectivity unprecedented in such simple, unbiased substrates. In general, the stereochemical outcome of these transformations can be rationalized by citing existing models for selectivity upon cyclization of substituted 5-hexenyl radicals. However, in a few specific instances, results obtained with alkylated vinylcyclopropyl substrates are not consistent with some of the predictions of these models.