Theoretical study of polar 2 + 2 cycloadditions
Abstract
By means of the MINDO/3 method the polar 2 + 2 cycloaddition of hydroxyethylene to 1,1 -dicyanoethylene and the dimerization of ethylene have been studied. For the polar reaction the transition state has dipolar character, while for the non-polar reaction it has a tricentric structure. The reaction mechanism and the importance of charge transfer are discussed.