Decarboxylative Sulfonylation of Carboxylic Acids under Mild Photomediated Iron Catalysis.

Organic sulfones are an important class of chemical compounds widely used in many research fields. The direct decarboxylative sulfonylation of carboxylic acids is attractive but challenging, particularly when iron is used as a metal catalyst. Herein, we describe a photoinduced iron-catalytic method for the synthesis of sulfones directly using carboxylic acids via a radical-based decarboxylation. This protocol is mild, highly efficient, and easy-to-operate. A broad scope of carboxylic acids and carbon electrophiles could be well tolerated. A mechanism involving the iron-catalyzed decarboxylation, radical transfer, single-electron reduction, and nucleophilic attack is proposed.

Mild Amide Synthesis Using Nitrobenzene under Neutral Conditions.

Amide synthesis is one of the most important transformations in organic chemistry due to the broad application in pharmaceutical drugs and organic materials. In this report, we describe a mild protocol for amide formation using the readily available nitroarenes as nitrogen sources and an inexpensive iron complex as a catalyst. Because of the use of the pH-neutral conditions and the avoidance of the strong oxidant or reductant, a wide range of aromatic and aliphatic aldehydes as well as nitroarenes with various functional groups could be tolerated well. A plausible mechanism is proposed based on the detailed studies, in which iron catalyst initiates the radical process and the solvent plays a key role as O-atom acceptor.