Stereoselective synthesis and semiempirical studies of spiro bridgehead bicyclic N-heterocycles <i style="">via</i> 1,3-dipolar cycloaddition reactions of azomethine ylides

Abstract

The reaction of acenaphthylene-1,2-dione with chiral cyclic secondary a-amino acids <i style="">viz.</i> l-proline gives rise to the intermediate azomethine ylide which has been trapped by acetylenic and ethylenic dipolarophiles to produce bridgehead bicyclic cycloadducts. The stereoselectivity of these cycloadditions have been ascertained by semiempirical calculations. The newly synthesized spiroazabicyclic compounds have been characterized by elemental analyses and spectral techniques (IR, ¹H NMR, ¹³C NMR and Mass).