Transition-Metal-Mediated Cascade Reactions: C,C-Dicyclopropylmethylamines by Way of Double C,C-σ-Bond Insertion into Bicyclobutanes

The organometallic multicomponent reaction of alkenyl zirconocene, alkynyl imine, and zinc carbenoid in the presence of dimethylzinc leads to novel C,C-dicyclopropylmethylamines. The formation of intermediate bicyclo1.1.0butanes represents the first synthetically useful example of a double C,C-sigma-bond insertion, and the increase in structural complexity from starting materials is highlighted by the formation of nine new C,C-bonds in the final product.