Asymmetric Transformations of Acyloxyphenyl Ketones by Enzyme−Metal Multicatalysis
摘要:
A multipathway process comprising several enzyme- and metal-catalyzed reactions has been explored for the asymmetric transformations of acyloxyphenyl ketones to optically active hydroxyphenyl alcohols in the ester forms. The process comprises nine component reactions in three pathways, all of which take place by the catalytic actions of only two catalysts, a lipase and a ruthenium complex. The synthetic reactions were carried out on 0.2-0.6 mmol scales for eight different substrates under an atmosphere of hydrogen (I atm) in toluene at 70 degreesC for 3 days. In most cases, the yields were high (92-96%) and the optical purities were excellent (96-98% ee), This work thus has demonstrated that enzyme-metal multicatalysis has great potential as a new methodology for asymmetric transformations.
(<i>S</i>)-Selective Dynamic Kinetic Resolution of Secondary Alcohols by the Combination of Subtilisin and an Aminocyclopentadienylruthenium Complex as the Catalysts
作者:Mahn-Joo Kim、Yong Il Chung、Yoon Kyung Choi、Han Ki Lee、Daeho Kim、Jaiwook Park
DOI:10.1021/ja036766r
日期:2003.9.1
A new procedure for the dynamic kinetic resolution (DKR) of racemic alcohols into single enantiomers is described. This procedure employs surfactant-treated subtilisin as an (S)-selective resolving catalyst and an aminocyclopentadienylruthenium complex as a racemizing catalyst. The DKR is performed best in the presence of an acyl donor such as trifluoroethyl butyrate in THF at room temperature. Eight simple secondary alcohols have been efficiently resolved with high optical purities and good yields. The subtilisin-based DKR is complementary in stereoselectivity to its lipase-based counterpart. For an acyl-carrying alcohol, both subtilisin- and lipase-based DKRs have proceeded equally well to give a pair of enantiomeric products (>99.5% ee each) with opposite optical rotations in high yields (94-95%).
Asymmetric Transformations of Acyloxyphenyl Ketones by Enzyme−Metal Multicatalysis
作者:Mahn-Joo Kim、Min Young Choi、Min Young Han、Yoon Kyung Choi、Jae Kwan Lee、Jaiwook Park
DOI:10.1021/jo026122m
日期:2002.12.1
A multipathway process comprising several enzyme- and metal-catalyzed reactions has been explored for the asymmetric transformations of acyloxyphenyl ketones to optically active hydroxyphenyl alcohols in the ester forms. The process comprises nine component reactions in three pathways, all of which take place by the catalytic actions of only two catalysts, a lipase and a ruthenium complex. The synthetic reactions were carried out on 0.2-0.6 mmol scales for eight different substrates under an atmosphere of hydrogen (I atm) in toluene at 70 degreesC for 3 days. In most cases, the yields were high (92-96%) and the optical purities were excellent (96-98% ee), This work thus has demonstrated that enzyme-metal multicatalysis has great potential as a new methodology for asymmetric transformations.