Chiral β-Amino Alcohols as Ligands for the Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of N-Phosphinyl Ketimines

Miguel Yus,David Guijarro,Óscar Pablo

doi:10.3390/app2010001

Miguel Yus, David Guijarro + Show 1 more

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https://doi.org/10.3390/app2010001

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Journal: Applied Sciences	Publication Date: Jan 9, 2012
Citations: 7	License type: CC BY 4.0

Affiliation: University of Alicante

Abstract

Some chiral β-amino alcohols have been evaluated as potential ligands for the ruthenium-catalyzed asymmetric transfer hydrogenation (ATH) of N-phosphinyl ketimines in isopropyl alcohol. The ruthenium complex prepared from [RuCl2(p-cymene)]2 and (1S,2R)-1-amino-2-indanol has shown to be an efficient catalyst for the ATH of several N-(diphenylphosphinyl)imines, affording the reduction products in very good isolated yields and enantiomeric excesses up to 82%. The inherent rigidity of the indane ring system present in the ligand seems to be very important to achieve good enantioselectivities.

Highlights

Amines are very important targets in organic chemistry since they are key substrates in organic synthesis, as well as in pharmaceutical and agrochemical research fields
Thereby, we present our preliminary results on the reduction of phosphinyl imines in isopropyl alcohol with ruthenium complexes bearing chiral β-amino alcohols
One of our main research lines has focused on the asymmetric synthesis of chiral amines by enantioselective addition of dialkylzinc reagents to N-(diphenylphosphinyl)imines using β-amino alcohols as ligands [47,48,49]

Summary

Introduction

Amines are very important targets in organic chemistry since they are key substrates in organic synthesis, as well as in pharmaceutical and agrochemical research fields. Chiral amines have been extensively used as resolving agents [1,2,3,4], starting materials for the preparation of therapeutic drugs [5] and chiral auxiliaries in asymmetric synthesis [6,7,8]. Synthetic chemists have made great efforts in order to implement efficient procedures for the preparation of chiral amines [9,10] among which the reduction of iminic substrates plays a capital role. The ATH of prochiral ketones affords enantiomerically enriched secondary alcohols with excellent results [12,13,14,15,16,17,18,19]

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