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A terminal alkyne-assisted protocol for the one-pot formation of a diverse range of arylamidines from a novel cascade reaction of in situ generated nitrile oxides, sulfonyl azides, terminal alkynes, and water by [3 + 2] cycloaddition and ring opening sequence was developed. The use of aryl oxime chlorides as the carbon source of the amidine group and the addition of water proved to be critical for the reaction. Moreover, terminal alkynes, which can lead to high yields of products by employing a less amount, may play a catalytic role in the reaction. A broader range of substrates was investigated.

A facile transition-metal-free protocol to form 2-iminoimidazo[1, 2-a]-pyridines bearing a –CHBr2 group and an aza-quaternary carbon center at the 3 position from N-(2-pyridyl)amidines substrates, in which the new heterocyclic skeletons constructed from amidines via radical reactions or nucleophilic substitution reactions are promoted only by CBr4 under mild conditions, is demonstrated. The reactions were realized by intramolecular CDC reaction involving C–N and C–C bond formation via the sequential C(sp3)–H bifunctionalization mode on the same carbon atom under mild conditions. Moreover, this work also provides an excellent and representative example for CBr4 as an efficient reagent to initiate radical reactions under initiator-free conditions or to give rise to nucleophilic substitution reactions only by base.

A new, step-economical and operationally simple access to unsubstituted 1,2-dihydroisoquinolin-3(4H)-imines by Cu-catalyzed MCRs under mild conditions is described. In addition, selective hydrolysis of imines to the corresponding 1,2-dihydroisoquinolin-3(4H)-ones under refluxed conc. HCl has also been investigated.