An unprecedented copper and in situ-generated triflic
acid relay-promoted
four-component cascade reaction of cyanamides, diaryliodonium triflates,
propargylic amines, and H2O was established for rapid and
concise construction of diverse five-membered cycloguanidines. Copper-catalyzed
guanidination/intramolecular hydroamination and in situ-generated
HOTf-accelerated hydration proceeded sequentially with high level
of chemoselectivity and regioselectivity, and six new bonds were simultaneously
built in high yields. Thus, diaryliodonium triflates served not only
as an arylation reagent but also as an internal acid promoter, establishing
an alternative strategy for highly efficient utilization of diaryliodonium
trifates.
Copper-catalyzed three-component and four-component cascade reactions of cyanamides, dirayliodonium triflates, and propargylamine were established for rapid construction of polysubstituted 2-aminoimidazoles and 2-iminoimidazoles using K2CO3 and pyridine as base, respectively. Each...
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