Heterocycles based on the chemistry of alkylidenecyclopropanes and (aza)-cyclopropenes

Alkylidenecyclopropyl, cyclopropenyl, or azacyclocyclopropenyl ketones or carboxylates have been demonstrated to be versatile starting materials for the synthesis of oxygen- and/or nitrogen-containing heterocycles. The reactivitics, and regioselectivities may be nicely controlled by subtle choice of the catalysts and reaction condition parameters.