Valorization of Ethanol: Ruthenium-Catalyzed Guerbet and Sequential Functionalization Processes

Abstract

We report a ruthenium-catalyzed tandem Guerbet–alkylation strategy for the valorization of ethanol. The products of ethanol upgrading (higher-order alcohols) undergo subsequent C–C bond forming reactions with four carbon pronucleophiles and one ylide. Studies into catalyst design led to the development of ClRu(5-Mebpi)(PPh3)2 (bpi = 1,3-bis(2′-pyridylimino)isoindolate) as a highly efficient catalyst for producing biofuels and value-added chemicals from ethanol via Guerbet and tandem Guerbet reactions. This catalyst affords 65% higher-order alcohols in short reaction times (2 h), providing the highest TON (155,890) and TOF (12,690 h–1) for a homogeneous catalyst reported to date.