A novel Rh(III)-catalyzed C─H annulation strategy has been devised to the synthesis of diarylisoquinolinones through a sequential C─H annulation of diarylethynes with 4H-benzo[d][1,3]oxazines. This is a direct method to generate highly functionalized diaryl isoquinolinones in a single-step .

Abstract

A novel Rh(III)-catalyzed [4 + 2] annulation of diarylacetylenes with 2-aryl-4H-benzo[d][1,3]oxazines is described to produce a new class of 3,4-diarylisoquinolinones through a ring-opening C─H annulation of benzo[d][1,3]oxazine moiety. This is the first report on C─H functionalazation of 2-aryl-4H-benzo[d][1,3]oxazines with diarylalkynes for the synthesis of 3,4-diarylisoquinolinone scaffolds. The scope of this method is well exemplified with diverse substrates bearing different functional groups including electron-rich and electron-deficient substituents.