Use of Phenyl Formate as a CO Surrogate for the Reductive Cyclization of Organic Nitro Compounds to Yield Different <i>N</i>-Heterocycles: Avoiding the Use of Autoclaves and Pressurized Gases

Abstract

The reductive cyclization of different organic nitro compounds by carbon monoxide, catalyzed by transition metal complexes, is a very efficient and clean strategy for the synthesis of many N-heterocycles. However, it requires the use of autoclaves and pressurized CO lines. In this paper, the authors will present the results obtained in their laboratories on the use of phenyl formate as a convenient CO surrogate, able to liberate carbon monoxide under reaction conditions and allowing for the use of a cheap glass pressure tube as a reaction vessel. In most cases, yields were better than those previously reported using pressurized CO, proving that the use of CO surrogates can be a viable alternative to the gaseous reagent.

Keywords

• nitroarenes
• nitroalkenes
• indoles
• carbazoles
• oxazines
• palladium