Iodine-catalyzed oxidative annulation: facile synthesis of pyrazolooxepinopyrazolones via methyl azaarene sp3 C-H functionalization

摘要

An iodine-catalyzed methyl azaarene sp(3) C-H functionalization has been developed for the synthesis of a seven-membered O-heterocyclic architecture containing three different heterocyclic aromatic hydrocarbons. This method can be applied to a wide range of substituted methyl azaarenes and diverse 2,4-dihydro-3H-pyrazol-3-ones, and brings about the efficient preparation of 2,9-dihydrooxepino[2,3-c:6,5-c ']dipyrazol-3(7H)-ones in high yields with the merits of low catalyst loading, good functional group tolerance and metal-free conditions.

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