A novel approach to the synthesis of substituted piperazines and their investigation as N- type calcium channel blockers is presented. A common scaffold exhibiting high activity as N- type blockers is N-substituted piperazine. Using recently developed titanium and zirconium catalysts, we describe the efficient and modular synthesis of 2, 5-asymmetrically disubstituted piperazines from simple amines and alkynes. The method requires only ...
