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.
Catalytic cyanomethylation of carbonyl compounds and imines with highly basic phosphine
作者:Satoru Matsukawa、Eri Kitazaki
DOI:10.1016/j.tetlet.2008.02.155
日期:2008.4
A highly basicphosphine, tris(2,4,6-trimethoxy phenyl)phosphine (TTMPP), catalyzes cyanomethylation using trimethylsilylacetonitrile (TMSCH2CN) to give the corresponding products in good to high yields, with both carbonyl compounds and imines.
A method of manufacturing a cyano compound by reacting a carbonyl compound with a nitrile compound having at least one α-hydrogen atom in the presence of a ligand and a metal compound of formula (III),
MX (III)
wherein M is a copper atom or a silver atom, and X is an alkoxy group, an alkyl group, an aryl group or an anionic residue.
Efficient Lipase-Catalyzed Kinetic Resolution and Dynamic Kinetic Resolution of β-Hydroxy Nitriles. Correction of Absolute Configuration and Transformation to Chiral β-Hydroxy Acids and γ-Amino Alcohols
Chemoenzymatic dynamickineticresolution of β-hydroxy nitriles 1 has been carried out using Candida antarctica lipase B and a ruthenium catalyst. The use of a hydrogen source to depress ketone formation in the dynamickineticresolution yields the corresponding acetates 2 in good yield and high enantioselectivity. It is shown that the ruthenium catalyst and the enzyme can be recycled when used in
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.