Copper‐Mediated (2‐Methylthio)aniline Directed Annulation of sp2 C−H Bonds with Primary Anilines

Directed amination of sp² C−H bonds is often limited to secondary, aliphatic amines. Herein, a method for coupling of ortho C−H bonds in (2-methylthio)aniline benzamides with primary anilines is developed. Copper(II) pivalate was crucial for successful annulation, which were tolerant of many functional groups. A control experiment revealed that directed mono-amination was the key step for further formation of the annulation product.

Abstract

A method for copper-mediated, directed functionalization of sp² C−H bonds in benzamides with primary anilines toward synthesis of indazolones is reported. Successful transformations relied on the use of a bidentate 2-methylthio aniline directing group. Functionalities including halogen, methylthio, cyano, ester, protected alcohol, and tertiary amine groups were compatible with reaction conditions. The method features a rare example for directed annulation of sp² C−H bonds with amines.

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