Enzyme-catalyzed synthesis or (R)-ketone-cyanohydrins and their hydrolysis to (R)-α-hydroxy-α-methyl-carboxylic acids
摘要:
(R)-Ketone-cyanohydrins (R)-2 are obtained with high enantioselectivity from aliphatic ketones 1 and HCN in organic solvents using (R)-oxynitrilase (EC 4.1.2.10) as catalyst. Acid catalyzed hydrolysis of the cyanohydrins (R)-2 affords the corresponding (R)-alpha-hydroxy-alpha-methyl-carboxylic acids (R)-3 without measurable racemization.
Approach to(R)- and (S)-ketone cyanohydrins using almond and apple meal as the source of (R)-oxynitrilase
作者:Eero Kiljunen、Liisa T. Kanerva
DOI:10.1016/s0957-4166(97)00110-9
日期:1997.5
The synthesis of aliphatic and aromatic (R)-ketone cyanohydrins through the addition of hydrogen cyanide to the corresponding ketones and the synthesis of the (S)-enantiomers through the kinetic resolution of racemic ketone cyanohydrins has been studied in the presence of almond or apple meal. Substrate tolerance of the (R)-oxynitrilases towards ketones ((RRC)-R-1-C-2=O) is highly restricted compared to that of structurally similar aldehydes, reactivity following the order of H>Me much greater than Et for R-2. In the case of aromatic methyl ketones reactivity difference (C6H5 much greater than p-Me-C6H4 for R-1) is notable. (C) 1997 Elsevier Science Ltd.
(R)-Ketone-cyanohydrins (R)-2 are obtained with high enantioselectivity from aliphatic ketones 1 and HCN in organic solvents using (R)-oxynitrilase (EC 4.1.2.10) as catalyst. Acid catalyzed hydrolysis of the cyanohydrins (R)-2 affords the corresponding (R)-alpha-hydroxy-alpha-methyl-carboxylic acids (R)-3 without measurable racemization.
(R)-Oxynitrilase catalyzed synthesis of (R)-ketone cyanohydrins
作者:Franz Effenberger、Stephan Heid
DOI:10.1016/0957-4166(95)00391-6
日期:1995.12
enantioselective addition of HCN to ethyl alkyl ketones 1 in diisopropyl ether yielding (R)-ethyl alkyl ketone cyanohydrins (R)-2, which are hydrolyzed under acid catalysis to give the α-hydroxy acids (R)-3. This (R)-oxynitrilase also catalyzes the enantioselective addition in aqueous citrate buffer (50 mM, pH 4.0), as demonstrated for the preparation of (R)-methyl alkyl ketone cyanohydrins (R)-5 which are obtained