Thiacrown Ether Technology in Lipase-Catalyzed Reaction: Scope and Limitation for Preparing Optically Active 3-Hydroxyalkanenitriles and Application to Insect Pheromone Synthesis
摘要:
Both reaction rate and enantioselectivity in Pseudomonas cepacia lipase (PCL)-catalyzed hydrolysis of 3-hydroxyalkanenitrile acetates were significantly changed by the addition of catalytic amounts of thiacrown ether (1,4,8,11-tetrathiacyclotetradecane). Although the-reaction rate of various nitriles was accelerated, the enantioselectivity greatly depended on the nature of the substrate. Among 10 substrates tested, thiacrown ether offered highest enantioselectivity in PCL-catalyzed hydrolysis of 1-(cyanomethyl)propyl acetate. Forty or more times this crown ether, molarity based on the enzyme, was required to attain an acceptably high reaction rate and enantioselectivity. Applying this technology, we succeeded in synthesizing the optically pure attractant pheromone of ant Myrmica scabrinodis (A), (R)-3-octanol and its antipode of (S)-isomer in good overall yields.
Biocatalytic and Structural Properties of a Highly Engineered Halohydrin Dehalogenase
作者:Marcus Schallmey、Robert J. Floor、Bernhard Hauer、Michael Breuer、Peter A. Jekel、Hein J. Wijma、Bauke W. Dijkstra、Dick B. Janssen
DOI:10.1002/cbic.201300005
日期:2013.5.10
Synergistic mutations: A halohydrindehalogenase with 37 mutations and improved catalytic properties for statin side chain synthesis has been biochemically characterized. Crystal structures with different ligands in the active site give insight into the way in which individual mutations contribute to enhanced stability and faster cyanolysis of epoxides and illustrate the importance of synergistic mutations
Increased Enantioselectivity and Remarkable Acceleration of Lipase-Catalyzed Transesterification by Using an Imidazolium PEG–Alkyl Sulfate Ionic Liquid
types of imidazolium salt ionicliquids were prepared derived from poly(oxyethylene)alkyl sulfate and used as an additive or coating material for lipase-catalyzedtransesterification in an organic solvent. A remarkably increasedenantioselectivity was obtained when the salt was added at 3-10 mol % versus substrate in the Burkholderia cepacia lipase (lipase PS-C)-catalyzed transesterification of 1-phenylethanol
The chiral pyrrolidine-substituted imidazolium cetyl-PEG10-sulfate (D-ProMe) derived from D-proline worked as an excellent activating agent of Burkholderia cepacia lipase; it is particularly interesting that the D-isomer of the imidazolium salt worked better than the L-isomer. This suggests that the imidazolium cation group directly interacts with the enzyme protein and causes preferable modification
A rational design of phosphonium ionic liquid for ionic liquid coated-lipase (IL1-PS)-catalyzed reaction has been investigated, and very rapid transesterification of secondary alcohols accomplished when IL1-PS was used as catalyst in 2-methoxyethoxymethyl(tri-n-butyl)phosphonium bis(trifluoromethanesulfonyl)amide ([P444MEM][NTf2]) as solvent while perfect enantioselectivity was maintaining. Increased Kcat value was suggested to be the most important factor in IL1-PS working the best in [P444MEM][NTf2] solvent.
Enantioselective Ring Opening of Epoxides with Cyanide Catalysed by Halohydrin Dehalogenases: A New Approach to Non-Racemic β-Hydroxy Nitriles
作者:Maja Majerić Elenkov、Bernhard Hauer、Dick B. Janssen
DOI:10.1002/adsc.200505333
日期:2006.3
Halohydrindehalogenases (HheA, HheB and HheC) were found to efficiently catalyse a carbon-carbon bond forming reaction between terminal aliphatic epoxides and cyanide, yielding β-hydroxynitriles. With all three enzymes nucleophilic ringopening of epoxides proceeds with high regioselectivity to the β-carbon atom. Activity, enantioselectivity and enantiopreference depend on the type of enzyme and