922735-29-3Relevant academic research and scientific papers
Elaboration on the access to (S)-4-(4-methylbenzyl)oxy-3-hydroxybutanenitrile, a key intermediate for statins, by combining the kinetic resolution of racemate and the recycle of undesired enantiomer
Sakamoto, Maki,Hamada, Manabu,Higashi, Toshinori,Shoji, Mitsuru,Sugai, Takeshi
experimental part, p. 96 - 100 (2010/11/04)
High enantioselectivity (E 94) was observed in Candida antarctica lipase B-catalyzed hydrolysis of the corresponding acetate of racemic title compound. The reaction rate of the slow (S)-isomer was effectively suppressed by lowering the reaction temperature from 25°C to 5°C, to allow a five times increase of the enantioselectivity. The ee of the (S)-isomer, reached 97.8% at the reasonable conversion (52%) as the unreacted recovery, and the repetition of the enzymatic reaction provided pure enantiomer. The undesired (R)-isomer was oxidized with IBX and reduced with whole-cell biocatalysis with Candida floricola JCM 9439 to (S)-isomer (63.2% ee), which serves as the enantiomerically enriched substrate for further lipase-catalyzed resolution. The combination of total processes provided over 50% yield of the pure (S)-isomer, exceeding the theoretical limit for the enantiomeric resolution of racemate.
A new and facile preparation of tert-butyl (3R,5S)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoate
Sun, Fenglai,Xu, Gang,Wu, Jianping,Yang, Lirong
, p. 2454 - 2461 (2008/03/13)
A facile method for the preparation of tert-butyl (3R,5S)-6-hydroxy-3,5-O-isopropylidene-3,5-dihydroxyhexanoate is described by a chemoenzymatic approach. In this method, one hydroxyl stereocenter at C5 is obtained with a high ee value (up to 98.0%) via an enzymatic transesterification resolution of l-chloro-3-(4-methylbenzyloxy)-2-propanol. The other hydroxyl stereocenter at C3 was built with 98.0% de, by acid-hydrolysis of a 1,3-diol-acetonide syn/anti-10. It is noteworthy that the reduction of β-hydroxy ketone 8 with sodium borohydride can be carried out smoothly in aqueous isopropyl alcohol with a high diastereomeric ratio syn/anti (drs:a) of 4.0:1.
Efficient lipase-catalyzed kinetic resolution of 4-arylmethoxy-3-hydroxybutanenitriles: application to an expedient synthesis of a statin intermediate
Sun, Fenglai,Xu, Gang,Wu, Jianping,Yang, Lirong
, p. 2907 - 2913 (2007/10/03)
The kinetic resolution of 4-arylmethoxy-3-hydroxybutanenitriles was investigated by lipase-catalyzed transesterification in organic solvents. A high enantioselectivity was obtained via reaction with vinyl acetate in a mixed solvent (n-heptane/acetonitrile 1:1), which was catalyzed by the lipase from Artgribacter sp. A better selectivity was demonstrated when the number of substituents on the aryl ring increased. (S)-4-Arylmethoxy-3-hydroxybutanenitriles can be obtained with enantiomeric excesses of up to 98.0% by this method. Furthermore we have developed a novel route to synthesize tert-butyl (S)-6-benzyloxy-5-hydroxy-3-oxohexanoate, a key intermediate for the preparation of HMG-CoA reductase inhibitors (statins).
