Copper-Catalyzed 1,2-Double Amination of 1-Halo-1-alkynes

Significance

A practical and versatile method for the synthesis of 2-substituted 1,2,3,4-tetrahydropyrazines and -oxazines is described, based on a new copper-catalyzed double amidation of haloacetylenes with 1,2- or 1,3-bis(sulfamides). The reaction conditions are mild and tolerate most important functional groups, including free hydroxy groups. 1,1-Dibromoolefins can also be used in this reaction instead of 1-bromoalkynes. The products are important intermediates, for example, in the synthesis of biologically relevant compounds.