Mechanochemical Asymmetric Transfer Hydrogenation of Diketones to Access Chiral 1,3-Diols under Solvent-Free Conditions

Abstract

The mechanochemical asymmetric transfer hydrogenation (ATH) of diketones to provide chiral 1,3-diols derivatives was developed in the presence of ruthenium complex under solvent-free conditions. This protocol benefits rapid reaction kinetics, no use of solvents and excellent enantioselectivities. In addition, the mechanochemical ATH reaction could be easily performed in gram-scale.

One-pot mechanochemical hydrogenation and acetylation of 4-nitrophenol to 4-aminophenol and paracetamol

“…18 Transfer hydrogenations of various reactants, such as carbonyls, ketones, and nitro derivatives have been increasingly discussed in the literature. 18,[20][21][22] However, a key question remains whether transfer hydrogenation is truly a preferred Green method of hydrogenation when compared to using elemental hydrogen. Indeed, transfer hydrogenation reagents suffer from pitfalls such as high cost, high molecular weight (compared to H 2 ), and the fact that elemental hydrogen tends to be involved in their main synthesis routes.…”

Cluster Preface: Development and Applications of Novel Ligands/Catalysts and Mechanistic Studies on Catalysis

“…4 The mechanochemical asymmetric transfer hydrogenation of diketones to provide chiral 1,3-diol derivatives with exceptionally high enantioselectivities has been developed in the presence of a chiral ruthenium complex under solvent-free conditions (T. Cheng & R. Liu). 5 A rhodium-catalyzed regioand enantioselective direct allylation of methyl ketones was realized by using a bisoxazolinephosphine ligand (C. Li). 6 8-Quinolinyl oxazoline ligands have been utilized in the Ni-catalyzed asymmetric reductive carbamoyl-alkylation of carbamoyl chloride tethered styrenes with unactivated alkyl iodides, providing access to valuable chiral oxindoles…”