Group 11 metal amide-catalyzed asymmetric cycloaddition reactions of azomethine imines with terminal alkynes.J Am Chem Soc. 2012 Dec 12; 134(49):20049-52.JA
We developed a 1,3-dipolar cycloaddition reaction of azomethine imines with terminal alkynes catalyzed by group 11 metal amides to provide N,N-bicyclic pyrazolidinone derivatives. This reaction afforded the cycloadducts in a unique 5,7-disubstituted manner. Furthermore, we succeeded in applying this catalysis to asymmetric reactions, and the desired heterocycles were produced in high yields with exclusive regioselectivity and high enantioselectivity. Mechanistic studies elucidated a stepwise reaction pathway and critical features that determine the regioselectivity.