Cycloaddition of phenyl azide to unsymmetrical azabicyclic alkenes

Abstract

Addition of phenyl azide to selected derivatives of the 2-azabicyclo[2.2.1]hept-5-ene, 2-azabicyclo[2.2.1]hept-5-en-3-one and 2-azabicyclo[2.2.2]oct-5-en-3-one ring systems is described. Modest levels of regioselectivity are observed; 100% exo-facial selectivity is found in the [2.2.1] systems but exo- and endo- adducts are formed from the [2.2.2] substrate allowing isolation of all four possible stereoisomers. Photolytic removal of dinitrogen from the triazolines gives aziridines which are potential precursors to stereospecifically functionalised aziridino-cyclopentanes and aziridino-cyclohexanes.