A novel synthesis of imidazoles via the cycloaddition of nitrile ylides to their imidoyl chloride precursors

Abstract

Generation of nitrile ylides, 4 and 22, via the base-catalysed 1,3-dehydrochlorination of imidoyl chlorides, 3 and 21, gives the imidazoles, 13, 23 and 24. These imidazoles are formed by the cycloaddition of the nitrile ylides, 4 and 22, to their precursor imidoyl chlorides, 3 and 21, and the observed regiochemistry of this cycloaddition has been rationalised by energy calculations on the frontier molecular orbitals of these reactants using semi-empirical (MOPAC PM3) methods.