144787-20-2Relevant articles and documents
Catalytic Asymmetric Epoxidation of Aldehydes with Two VANOL-Derived Chiral Borate Catalysts
Gupta, Anil K.,Yin, Xiaopeng,Mukherjee, Munmun,Desai, Aman A.,Mohammadlou, Aliakbar,Jurewicz, Kelsee,Wulff, William D.
, p. 3361 - 3367 (2019/02/16)
A highly diastereo- and enantioselective method for the epoxidation of aldehydes with α-diazoacetamides has been developed with two different borate ester catalysts of VANOL. Both catalytic systems are general for aromatic, aliphatic, and acetylenic aldehydes, giving high yields and inductions for nearly all cases. One borate ester catalyst has two molecules of VANOL and the other only one VANOL. Catalysts generated from BINOL and VAPOL are ineffective catalysts. An application is shown for access to the side-chain of taxol.
Bioresolution production of (2R,3S)-Ethyl-3-phenylglycidate for chemoenzymatic synthesis of the taxol C-13 side chain by galactomyces geotrichum ZJUTZQ200, a new epoxide-hydrolase-producing strain
Wei, Chun,Ling, Jinlong,Shen, Honglei,Zhu, Qing
, p. 8067 - 8079 (2014/07/08)
A newly isolated Galactomyces geotrichum ZJUTZQ200 strain containing an epoxide hydrolase was used to resolve racemic ethyl 3-phenylglycidate (rac-EPG) for producing (2R,3S)-ethyl-3-phenylglycidate ((2R,3S)-EPG). G. geotrichum ZJUTZQ200 was verified to be able to afford high enantioselectivity in whole cell catalyzed synthesis of this chiral phenylglycidate synthon. After the optimization of the enzymatic production and bioresolution conditions, (2R,3S)-EPG was afforded with high enantioselectivity (e.e.S > 99%, E > 49) after a 8 h reaction. The co-solvents, pH buffer solutions and substrate/cell ratio were found to have significant influences on the bioresolution properties of G. geotrichum ZJUTZQ200. Based on the bioresolution product (2R,3S)-EPG, taxol's side chain ethyl (2R,3S)-3-benzoylamino-2-hydroxy- 3-phenylpropionate was successfully synthesized by a chemoenzymatic route with high enantioselectivity (e.e.S > 95%).
Asymmetric epoxidation of cis-alkenes with arabinose-derived ketones: enantioselective synthesis of the side chain of Taxol
Shing, Tony K.M.,Luk, To,Lee, Chi M.
, p. 6621 - 6629 (2007/10/03)
The ee values of asymmetric epoxidation of cis-ethyl cinnamate 15 with arabinose-derived ketones as catalyst and Oxone as the terminal oxidant were found to increase inversely with the size of the catalyst acetal blocking group. Ketone catalyst
Synthesis of taxol, analogs and intermediates with variable A-nng side chains
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Page 14, (2010/01/31)
An efficient protocol for the synthesis of taxol, taxol analogs, and their intermediates is described. The process includes the attachment of the taxol A-ring side chain to baccatin III and for the synthesis of taxol and taxol analogs with variable A-ring side chain structures. A rapid and highly efficient esterification of O-protected isoserine and 3-phenylisoserine acids having N-benzyoloxycarbonyl groups to the C-13 hydroxyl of 7-O-protected baccatin III is followed by a deprotection-acylation sequence to make taxol, calphalomanninne and various analogs, including photoaffinity labeling candidates.
Regio and stereoselective opening of chiral cyclic sulfates with MgBr2- Et2O : A practical strategy for the synthesis of (2R,3S)-(-)-N-benzoyl-3- phenylisoserine ethyl ester (taxol side chain)
Nandanan,Phukan, Prodeep,Sudalai
, p. 283 - 286 (2007/10/03)
The reaction of 4(S)-carbethoxy-5(R)-phenyl-1,3,2-dioxathiolane-2,2- dioxide 4 with MgBr2.Et2O readily proceed, regio- and stereoselectively at the benzylic position to afford the desired bromohydrin 5 in excellent yield which led to
Stereospecific preparation of glycidic esters from 2-chloro-3-hydroxyesters. Application to the synthesis of (2R,3R)-3-phenylisoserine
Cabon,Buisson,Larcheveque,Azerad
, p. 2211 - 2218 (2007/10/03)
Cis- and trans-glycidic esters may be synthesized in high enantiomeric purities by cyclisation with potassium carbonate in DMF of the corresponding syn- or anti-2-chloro-3-hydroxyesters, prepared by microbial reduction of 2-chloro-3-oxoesters. In contrast, more basic media such as sodium ethylate afford exclusively the trans-isomer, whatever the stereochemistry of the starting 2-chloro-3-hydroxyester is. Cyclisation of deuterated compounds showed that this result was due to a rapid isomerisation of the syn esters into anti isomers before cyclisation. An application of this reaction to the synthesis of (2R,3R)-3-phenylisoserine is described.
Improved protection and esterification of a precursor of the taxotere and taxol side chains
Commercon,Bezard,Bernard,Bourzat
, p. 5185 - 5188 (2007/10/02)
(4S,5R)-N-BOC-2,2-dimethyl-4-phenyl-5-oxazolidinecarboxylic acid 8 was prepared and efficiently esterified by conveniently protected baccatins 9a,b. Smooth deprotection in formic acid gave the N-deprotected intermediates of Taxotere and taxol. This protocol did not generate any epimerization at C-2′ and constitutes a pratical method to prepare Taxotere, taxol and analogs.
CHEMO-ENZYMATIC SYNTHESIS OF ALL ISOMERIC 3-PHENYLSERINES AND -ISOSERINES
Hoenig, H.,Seufer-Wasserthal, P.,Weber, H.
, p. 3841 - 3850 (2007/10/02)
The synthesis of all isomers of 3-phenylserines and 3-phenylisoserines in enantiomerically pure form is presented.Diastereomerically pure educts (threo/erythro-2-azido-3-butanoyloxy-3-phenyl-propionic esters, threo/erythro-3-azido-2-butanoyloxy-3-phenylpropionic esters, threo-2-butanoylamino-3-butanoyloxy-3-phenylpropionic ester, erythro-3-butanoylamino-2-butanoyloxy-3-phenyl-propionamide) were prepared from cinnamic acid derivatives or via aldol condensations of benzaldehyde and suitable enolates in few steps.These racemates were resolved with lipases from Candida cylindracea (CC) and Pseudomonas fluorescens (P) and the obtained products were hydrogenated to 3-phenylserines and -isoserines.The influence of the acyl group in the enzymatic resolution of erythro-3-azido-2-acyloxy-3-phenylpropionic esters was investigated.