Iridium-Catalyzed Transfer Hydrogenation of Ketones and Aldehydes Using Glucose as a Sustainable Hydrogen Donor

Masato Yoshida,Ken-Ichi Fujita,Takuya Shimbayashi,Ryota Hirahata,Takayoshi Inoue

doi:10.3390/catal9060503

Masato Yoshida, Ken-Ichi Fujita + Show 3 more

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https://doi.org/10.3390/catal9060503

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Journal: Catalysts	Publication Date: May 31, 2019
Citations: 21	License type: CC BY 4.0

Affiliation: Kyoto University

Abstract

A new catalytic system for transfer hydrogenation of carbonyl compounds using glucose as a hydrogen donor was developed. Various ketones and aldehydes were efficiently converted to corresponding alcohols with two equivalents of glucose in the presence of a small amount (0.1 to 1.0 mol%) of iridium catalyst that had a functional ligand. In this catalytic system, transfer hydrogenation reactions proceeded based on the cooperativity of iridium and a functional ligand. It should be noted that environmentally benign water could have been used as a solvent in the present catalytic system for the reduction of various carbonyl substrates. Furthermore, the reaction scope could be extended by using N,N-dimethylacetamide as a reaction solvent.

Highlights

Reductive conversion of carbonyl compounds to alcohols is one of the most important and fundamental reactions in the field of synthetic organic chemistry
Reactions were conducted in a sealed stainless-steel reactor using 5a (2.0 mmol) and glucose◦ (4.0 in water (3.0 mL) in the presence of catalytic amounts of iridium complex and base for 20 h at 80 C to mmol) in water (3.0 mL) in the presence of catalytic amounts of iridium complex and base for 20 h at 120 ◦ C
We developed a new system for transfer hydrogenation of various ketones and aldehydes using glucose as a hydrogen donor catalyzed by a small amount of iridium complex

Summary

Introduction

Reductive conversion of carbonyl compounds to alcohols is one of the most important and fundamental reactions in the field of synthetic organic chemistry. This method has been predominantly used to prepare various alcohols. For small-scale laboratory experiments, reduction of carbonyl compounds to alcohols is often performed with stoichiometric amounts of metal hydride reductant, such as lithium aluminum hydride or sodium borohydride. Both the aforementioned methods are well-established; hydrogen poses safety issues owing to its explosive nature. Using a metal hydride reductant adversely affects the chemoselectivity of the reaction and produces a stoichiometric amount of waste

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