Synthesis of quinazolinones via Cp*Co(III)-catalyzed C-H functionalization of primary amides with oxadiazolones.

ABSTRACT

Multi-heteroatom heterocycle synthesis through direct C-H bond activation is methodologically appealing but synthetically challenging. An efficient double C-N bond formation sequence to prepare quinazolinones utilizing primary amides and oxadiazolones in a catalytic redox-neutral [CoCp*(CO)I2]/AgSbF6 system, where oxadiazolone could function as an internal oxidant to maintain the catalytic cycle, is reported. Amide-directed C-H bond activation and oxadiazolone decarboxylation are key to the success of this traceless, atom- and step-economic, and cascade approach for the construction of the quinazolinone skeleton.