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Cu-catalyzed ring opening reaction of 2H-azirines with terminal alkynes: an easy access to 3-alkynylated pyrroles.

A highly efficient Cu-catalyzed ring expansion reaction of 2H-azirines with terminal alkynes has been developed. This transformation provides a powerful method for the synthesis of 3-alkynyl polysubstituted pyrroles under mild conditions in good yields. The direct transformation process, specific selectivity, and good tolerance to a variety of substituents make it an alternative approach to the reported protocols.