Synthesis of imidazo[2,1-a]isoquinolin-5-ones via C-H imidoylmethylation/oxidation/cyclization cascade of 2-arylbenzimidazoles with CF3-imidoyl sulfoxonium ylides by Rh(III)/Cu(II) relay catalysis.

A direct C-H imidoylmethylation and subsequent oxidation/cyclization reaction of 2-arylbenzimidazoles with CF3-imidoyl sulfoxonium ylides via Rh(III)/Cu(II) relay catalysis has been developed. This reaction proceeded under mild conditions in an O2 atmosphere to afford an array of CF3-decorated imidazo[2,1-a]isoquinolin-5-ones, where O2 acts as the oxygen donor for carbonyl group formation. This transformation involved an unprecedented cascade process including Rh(III)-catalyzed C-H imidoylmethylation and Cu(II)-mediated oxidation followed by cyclization. Notably, antitumor activity study revealed that some synthetic products exhibit promising antiproliferative activity against several cancer cell lines.