Promising Applications of Polyethyleneimine as a Ligand in Rhodium-Catalyzed Tandem Hydroformylation/Hydrogenation of Olefins

Simplified Version of the Eschweiler–Clarke Reaction

“…The authors demonstrated that ammonia and its salts can be transformed into trimethylamine under heating with formaldehyde and HCOOH in sealed vessels. Subsequently, this reaction attracted extensive attention and was applied in multiple cases without any strong modifications in natural product synthesis, materials chemistry, and medicinal chemistry. − In particular, in the preparation of pharmaceutical substances, HCOOH as a reducing agent is one of the top five most frequently used reductants in the reductive amination . The inherent problem of the classical variant of the Eschweiler–Clarke reaction is the large excess of concentrated HCOOH (∼9 M) required for the reaction to take place.…”