Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/24973
Title: Studies on the synthesis of Squaric Acid Ephedrine and their application in Asymmetric Catalytic Borane reduction of Prochiral Ketones
Authors: Lu, SM
Zhou, HB
Zhang, J
Xie, RG
Zhou, ZY
Chan, ASC
Yang, DK
Keywords: Asymmetric catalysis
Chiral oxazaborolidines
Reduction of aryl ketones
Squaric ephedrine amide
Issue Date: 2001
Publisher: Higher Education Press
Source: Kao teng hsueh hsiao hua heush hsueh pao/ Chemical journal of Chinese universities, 2001, v. 22, no. 11, p. 1850-1851 How to cite?
Journal: Kao Teng Hsueh Hsiao Hua Heush Hsueh Pao/ Chemical Journal of Chinese Universities 
Abstract: Seven squaric acid ester amides or squaric acid diamides have been conveniently prepared by the reaction of natural ephedrine and squaric acid diesters, in which the later can be sythesized by refluxing squaric acid in the corresponding alcohols. When squaric acid amide ester 4a reacted with alkyl amines or was treated with aqueous sodium hydrosulfide, the new ligands which contain nitrogen or sulfur atom at C-3 of squaric acid were obtained. Five ligands were synthesized for the first time. The chiral oxazaborolidines formed in situ have been used in the enantioselective borane reduction of prochiral ketones and diketones to afford the alcohols in the range 85%-98% yields and 52.5%-87.4% enantiomeric excess respectively. All new ligand structures were comfirmed by IR, 1H NMR, MS and elemental analysis, the crystal structure of compound 4b was lerrified by X-ray diffraction.
URI: http://hdl.handle.net/10397/24973
ISSN: 0251-0790
Appears in Collections:Journal/Magazine Article

Access
View full-text via PolyU eLinks SFX Query
Show full item record

Page view(s)

34
Last Week
5
Last month
Checked on Apr 23, 2017

Google ScholarTM

Check



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.