Divergent amine-catalyzed [2+2] annulation of allenoates with azodicarboxylates: facile synthesis of 1,2-diazetidines

In this Letter, we described a distinct DABCO-catalyzed [2+2] annulation reaction of allenoates with azodicarboxylates which affords 3-alkylidene-1,2-diazetidines in moderate yields with excellent stereo- and regioselectivity. This reaction constitutes the first example of Lewis base-catalyzed annulation of allenoates with azodicarboxylates, and showcases a divergent reactivity between phosphines and amines. (C) 2015 Elsevier Ltd. All rights reserved.