Nouvelle cyclopentannelation regioselective par une sequence tandem: Ouverture electrophile/cycloaddition [3+2] entre cetones methylenecyclopropaniques et l'allyltrimethylsilane

Article abstract of DOI:10.1016/S0040-4020(98)00335-4

The TiCl₄-mediated reactivity of five complementary substituted methylenecyclopropyl ketones with allyltrimethylsilane has been studied. The regioselectivity of the reaction, which affords functionalized methylene and/or alkylidenecyclopentanes in good yields, depends on the substitution of the cyclopropanic carbon α to the carbonyl function. The reaction occurs via a stereoselective cleavage of the carbocycle followed by a tandem [3+2] cycloaddition of the resultant (Z)-1, 3-zwitterion with allyltrimethylsilane that acts as the 1,2-partner in a synclinal approach.