Construction of nine-membered N,N,O-heterocycles <i>via</i> Pd-catalyzed [6+3] dipolar cycloaddition

Abstract

A new approach for the synthesis of 9-membered N,N,O-heterocycles by Pd-catalyzed [6+3] dipolar cycloaddition of <i>N</i>-iminoisoquinolinium ylides and 2-vinyl oxetanes has been developed. The scope of this cycloaddition was demonstrated with 28 examples. This is another important synthetic strategy for medium-sized rings by employing <i>N</i>-iminoisoquinolinium ylides as ternary synthons.