Synthesis of Fused or Spiro Polyheterocyclic Compounds via the Dehydrogenative Annulation Reactions of 2-Arylindazoles with Maleimides

• DOI: 10.1021/acs.orglett.9b01889
• Publication Date: 2019-09-04T18:32:42Z
• Authors: Chenhao Guo; Bin Li; Huilai Liu; Xiaopeng Zhang; Xinying Zhang; Xuesen Fan
• Keywords: Annulation; Maleimide; Indazole; Metalation

A dehydrogenative annulation of 2-arylindazoles with maleimides for the switchable synthesis indazolo[2,3-a]pyrrolo[3,4-c]quinolinones or spiroindolo[1,2-b]indazole-11,3′-pyrrolidinones is presented. Mechanistically, formation title compounds involves a Rh(III)-catalyzed C–H metalation 2-arylindazole, followed by maleimide insertion and intramolecular cyclization. Interestingly, selectivity to form fused spiro could be switched resorting different additives. The notable features this protocol include simple substrates excellent atom economy regioselectivity.