Metal-involving generation of aminoheterocycles from N-substituted cyanamides: toward sustainable chemistry (a minireview)

Abstract

This review is focused on progress in the area of metal-involving reactions of cyanamides leading to aminosubstituted heterocycles. The consideration covers metal-mediated cyanamide–amidoxime coupling giving 5-aminosubstituted 1,2,4-oxadiazoles and cycloaddition of nitrones or azides to cyanamide species furnishing 5-aminosubstituted 2,3-dihydro-1,2,4-oxadiazoles and 5-aminotetrazoles, respectively. Gold-catalyzed heterocyclization of cyanamides and acetylenes providing 2-aminooxazole systems is also considered. All these reaction schemes are discussed from viewpoints of sustainable processes with particular focus on how application of metal-involving reactions to organic transformations of cyanamides provides milder reaction conditions, increase yields of target products, and reduce number of reactions steps thus making the chemistry of cyanamides more environmentally benign.