Ti–Mg-Catalyzed Carbozincation of N-Benzyl-N-(but-3-en-1-yl)hept-2-yn-1-amine with Et₂Zn

It has been shown for the first time that the Ti-Mg-catalyzed carbozincation reaction of N-benzyl-N-(but-3-en-1-yl)hept-2-yn-1-amine with Et₂Zn involves the regio- and stereoselective formation of (Z)-1-benzyl-4-methyl-3-pentylidenepiperidine. The effect of the solvent on the Ti-Mg-catalyzed heterocyclization of N-benzyl-N-(but-3-en-1-yl)hept-2-yn-1-amine was studied. A mechanism of the carbozincation of N-homoallyl-substituted propargylamine with Et₂Zn in the presence of catalytic amounts of Ti(O-iPr)₄ and EtMgBr has been proposed.