Ir(iii)-Catalyzed [4 + 2] cyclization of azobenzene and diazotized Meldrum's acid for the synthesis of cinnolin-3(2H)-one?

Organic & Biomolecular Chemistry Pub Date: 2019-02-06 DOI: 10.1039/C8OB03214A

Abstract

The first report on Ir(III)-catalyzed C–H alkylation/cyclization of azobenzene with diazotized Meldrum's acid is described for the synthesis of cinnolin-3(2H)-one derivatives under mild conditions. Controlled experiments led to the isolation of intermediate ortho-alkylated product of azobenzene, which was converted to both cinnolin-3(2H)-one-4-carboxylic acid and its ester derivative. Additionally, the iridacyclic complex of azobenzene was isolated and found to be an active intermediate in the catalytic cycle.

Graphical abstract: Ir(iii)-Catalyzed [4 + 2] cyclization of azobenzene and diazotized Meldrum's acid for the synthesis of cinnolin-3(2H)-one
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