Minor enantiomer recycling: metal catalyst, organocatalyst and biocatalyst working in concert.
Chemistry
; 15(44): 12107-13, 2009 Nov 09.
Article
em En
| MEDLINE
| ID: mdl-19768712
ABSTRACT
A minor enantiomer recycling one-pot procedure employing two reinforcing chiral catalysts has been developed. Continuous regeneration of the achiral starting material is effected via selective enzyme-catalyzed hydrolysis of the minor product enantiomer from Lewis acid-Lewis base catalyzed addition of acyl cyanides to prochiral aldehydes in a two-phase solvent system. The process provides O-acylated cyanohydrins in close to perfect enantioselectivities, higher than those obtained in the direct process, and in high yields. A combination of a (S,S)-salen Ti Lewis acid and Candida antarctica lipase B provides the products with R absolute configuration, whereas the opposite enantiomer is obtained from the (R,R)-salen Ti complex and Candida rugosa lipase.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Compostos Orgânicos
/
Biocatálise
/
Metais
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article