Semiempirical AM1 investigation of geometric and electronic effects in Myers' cyclization reaction

Semiempirical quantum chemical AM1 methodology has been employed to find ou t various geometric and electronic effects in Myers' cyclization reaction. Reasonable trends in the activation harriers with the variation in the dist ance between the reactive sites are obtained. The proximity criterion is op erative in allene-ene-yne cyclizations too, But the effect is less than in corresponding Bergman cyclizations. The computed results have been interpre ted on the basis of the geometric features contributing to the overall acti vation enthalpies.