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

Department of Chemistry, Calcutta University, 92, A. P. C. Road, Calcutta-700 009, India

Manuscript received 10 August 1999, revised 4 January 2000, accepted 6 April 2000

Semiempirical quantum chemical AM1 methodology has been employed to find out various geometric and electronic effects in Myers' cyclization reaction. Reasonable trends in the activation barriers with the variation in the distance between the reactive sites are obtained. The proximity criterion is operative in allene-ene-yne cyclizations too, but the effect is less than in corresponding Bergman cyclizations. The computed results have been interpreted on the basis of the geometric features contributing to the overall activation enthalpies.