Homogeneous cobalt-catalyzed reductive amination for synthesis of functionalized primary amines

Kathiravan Murugesan,Anke Spannenberg,Vishwas G Chandrashekhar,Rajenahally V Jagadeesh,Helfried Neumann,Zhihong Wei,Matthias Beller,Haijun Jiao

doi:10.1038/s41467-019-13351-7

Kathiravan Murugesan, Anke Spannenberg + Show 6 more

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https://doi.org/10.1038/s41467-019-13351-7

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Journal: Nature Communications	Publication Date: Nov 29, 2019
Citations: 59	License type: open-access

Affiliation: Leibniz Institute for Catalysis

Abstract

The development of earth abundant 3d metal-based catalysts continues to be an important goal of chemical research. In particular, the design of base metal complexes for reductive amination to produce primary amines remains as challenging. Here, we report the combination of cobalt and linear-triphos (bis(2-diphenylphosphinoethyl)phenylphosphine) as the molecularly-defined non-noble metal catalyst for the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds, gaseous ammonia and hydrogen in good to excellent yields. Noteworthy, this cobalt catalyst exhibits high selectivity and as a result the -NH2 moiety is introduced in functionalized and structurally diverse molecules. An inner-sphere mechanism on the basis of the mono-cationic [triphos-CoH]+ complex as active catalyst is proposed and supported with density functional theory computation on the doublet state potential free energy surface and H2 metathesis is found as the rate-determining step.

Highlights

The development of earth abundant 3d metal-based catalysts continues to be an important goal of chemical research
Organometallic complexes based on palladium[12,13,14], ruthenium[15,16], rhodium[17,18,19], platinum[20,21], and iridium[22,23] have revolutionized organic synthesis
We report that the specific combination of cobalt and bisphenylphosphine allows the reductive amination of broad variety of aldehydes and ketones with ammonia in presence of molecular hydrogen, and this enables the synthesis of a series of functionalized and structurally diverse linear and branched benzylic, heterocyclic and aliphatic amines

Summary

Introduction

The development of earth abundant 3d metal-based catalysts continues to be an important goal of chemical research. We report the combination of cobalt and linear-triphos (bis(2-diphenylphosphinoethyl)phenylphosphine) as the molecularly-defined non-noble metal catalyst for the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds, gaseous ammonia and hydrogen in good to excellent yields. This cobalt catalyst exhibits high selectivity and as a result the -NH2 moiety is introduced in functionalized and structurally diverse molecules. We report that the specific combination of cobalt and bis (diphenylphosphinoethyl)phenylphosphine (so-called linear triphos) allows the reductive amination of broad variety of aldehydes and ketones with ammonia in presence of molecular hydrogen, and this enables the synthesis of a series of functionalized and structurally diverse linear and branched benzylic, heterocyclic and aliphatic amines. Our present work is complementary to the known syntheses of primary benzylic and aliphatic amines by direct catalytic amination of alcohols[58,59,60,61] and hydroamination using ammonia[45,62,63,64]

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