Dramatic Enhancement of Enantioselectivity of Biotransformations of β-Hydroxy Nitriles Using a Simple O-Benzyl Protection/Docking Group
摘要:
Catalyzed by the Rhodococcus erythropolis AJ270 whole cell catalyst, the O-benzylated beta-hydroxy alkanenitriles underwent remarkably high enantioselective biotransformations, whereas the biotransformations of free beta-hydroxy alkanenitriles gave very low enantioselectivity. The easy manipulations of O-protection and O-deprotection, excellent chemical and enantiomeric yields of biotransformations, along with the scalability render this enzymatic transformation attractive and practical for the synthesis of highly enantiopure beta-hydroxy alkanoic acids and their amide derivatives.
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
Efficient nickel catalyst for coupling of acetonitrile with aldehydes
作者:Lei Fan、Oleg. V. Ozerov
DOI:10.1039/b505778g
日期:——
A Ni complex of a diarylamido-based PNP ligand is an efficient and robust catalyst for coupling of acetonitrile with aldehydes.
二芳基酰胺基 PNP 配体的镍络合物是乙腈与醛偶联的高效、稳健催化剂。
[EN] SYNTHESIS METHOD APPLIED TO KRAS INHIBITOR DRUG HETEROCYCLIC INTERMEDIATE<br/>[FR] PROCÉDÉ DE SYNTHÈSE APPLIQUÉ À UN INTERMÉDIAIRE HÉTÉROCYCLIQUE DE MÉDICAMENTS INHIBITEURS DE KRAS<br/>[ZH] 一种应用于KRAS抑制剂类药物杂环中间体的合成方法
Thiacrown Ether Technology in Lipase-Catalyzed Reaction: Scope and Limitation for Preparing Optically Active 3-Hydroxyalkanenitriles and Application to Insect Pheromone Synthesis
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.