Fragmentation of Optically Active (1-Phenylethyl)- and (1-Naphthylethyl)ureas in Refluxing Alcohols: Easy Preparation of Optically Active Amines of High Optical Purity

1986 ◽  
Vol 69 (6) ◽  
pp. 1486-1497 ◽  
Author(s):  
Bernhard Schönenberger ◽  
Arnold Brossi
Keyword(s):  
Optical Purity ◽  
Optically Active ◽  
High Optical Purity

Preparation of secondary alcohols of high optical purity

1986 ◽  
Vol 51 (2) ◽  
pp. 401-403 ◽  
Author(s):  
Otakar Červinka ◽  
Anna Fábryová ◽  
Irina Sablukova
Keyword(s):  
Nmr Spectroscopy ◽  
Optical Purity ◽  
Optically Active ◽  
Secondary Alcohols ◽  
Lithium Aluminium Hydride ◽  
Enantioselective Reduction ◽  
H Nmr ◽  
Lithium Aluminium ◽  
High Optical Purity ◽  
Optically Pure

Partially resolved enantiomers of optically active alcohols I-V, obtained by enantioselective reduction of the corresponding ketones with lithium aluminium hydride in the presence of (-)-quinine, were converted into crystalline 3,5-dinitrobenzoates or phenylcarbamates. The esters of the nearly optically pure enantiomers were separated by crystallization from the generally more soluble esters of the racemates. Optical purity of the hydrolytically liberated alcohols was determined by 1H NMR spectroscopy in the presence of chiral shifting agents.

Applications of Optically Active Aryl Cyanohydrins in the Synthesis of α-Hydroxy Aldehydes, α-Hydroxy Ketones and β-Hydroxy Amines

1990 ◽  
Vol 43 (12) ◽  
pp. 2045 ◽  
Author(s):  
WR Jackson ◽  
HA Jacobs ◽  
GS Jayatilake ◽  
BR Matthews ◽  
KG Watson
Keyword(s):  
Optical Purity ◽  
Optically Active ◽  
Aryl Aldehydes ◽  
High Optical Purity ◽  
Hydroxy Ketones ◽  
Hydroxy Aldehydes

Cyanohydrins, prepared in high optical purity from aryl aldehydes, have been converted into α- hydroxy aldehydes, β- hydroxy ketones and β- hydroxy amines without any racemization and frequently with good stereoselectivity for the erythro-diastereoisomer (>90%) at the newly introduced stereogenic centre.

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