Reactions of a 2H-azirine with electron-rich olefins; synthesis of dimethyl pyrrole-2,3-dicarboxylates
Abstract
The electron-deficient 2H-azirine(2) reacts with enamines and α-oxo phosphorus ylides to give the pyrrole-2,3-dicardoxylates (3)–(6); α-ester phosphorus ylides on the contrary, furnish the substituted vinyliminophosporanes (7) and (8).