Progress in 1,3-dipolar cycloadditions in the recent decade: an update to strategic development towards the arsenal of organic synthesis

Abstract

Scheme 1. Atom economic synthesis of triazolobenzodiazepines. 1,3-Dipolar cycloaddition of primary amino esters, aldehydes, and activated alkenes is a well-established three-component reaction [16][17][18][19][20][21]. The azomethine ylides derived from deprotonation of iminium ions are CO2R-stabilized ylides A (Figure 2A) [22][23][24][25][26][27][28][29][30]. In recent years, our lab has reported a series of azomethine ylides A-based [3 + 2] cycloadditions for diverse heterocyclic scaffolds [31][32][33][34][35], including one-pot [3 + 2] and click reactions for triazolobenzodiazepines [32]