Synthesis of Unprotected Carboxy Indazoles via Pd-Catalyzed Carbonylation

Abstract

The first published synthesis of unprotected carboxy indazoles from the corresponding bromoindazoles is described. This is achieved via Pd(II)-catalyzed carbonylation and is demonstrated to work on a variety of indazoles.

GRAPHICAL ABSTRACT

Keywords:

• Carbonylation
• carboxylic acids
• halides
• indazoles
• palladium

ACKNOWLEDGMENT

We gratefully acknowledge the help of Gemma Chew in compiling this paper.

Notes

Note. Conditions: PdCl₂, BINAP, CO (40 bar), Et₃N, MeOH/CH₃CN.

^a Yields refer to isolated products.

Note. Conditions: Pd(dppf)Cl₂, CO (3 bar), NaOAc, MeOH/DMF.

^a Yields refer to isolated products.