(S)-Mandelate-Mediated Dynamic Kinetic Resolution of α-Bromo Esters for Asymmetric Syntheses of Aminoflavones, Dihydroquinoxalinones and Dihydrobenzoxazinones
作者:Yong Sun Park、Yoon Min Lee
DOI:10.3987/com-09-11700
日期:——
(S)-Mandelate-mediated dynamickineticresolution of α-bromoesters in nucleophilicsubstitution reaction has been investigated. Reactions of various aryl amine nucleophiles in the presence of TBAI and DIEA can provide the substitution products 2 and 7-19 up to 95% yield and 96:4 dr. Also, the simple procedure with spontaneous removal of the chiral auxiliary provides a practical protocol for asymmetric
[Ir(P−OP)]-Catalyzed Asymmetric Hydrogenation of Diversely Substituted C═N-Containing Heterocycles
作者:José Luis Núñez-Rico、Anton Vidal-Ferran
DOI:10.1021/ol400854a
日期:2013.4.19
Iridium(I) complexes of enantiomerically pure phosphine-phosphite ligands ([Ir(Cl)(cod)(P—OP)]) efficiently catalyze the enantioselectivehydrogenation of diverse C═N-containing heterocyclic compounds (benzoxazines, benzoxazinones, benzothiazinones, and quinoxalinones; 25 examples, up to 99% ee). A substrate-to-catalyst ratio as high as 2000:1 was reached.
L-Lactate-mediated Dynamic Kinetic Resolution of α-Bromo Esters for Asymmetric Syntheses of α-Amino Acid Derivatives
作者:Yelim Kim、Kon Ji Park、Yun Soo Choi、Myung-Su Lee、Yong Sun Park
DOI:10.5012/bkcs.2013.34.8.2531
日期:2013.8.20
effective for the dynamic resolution of α-halo esters. 3 In our continuous efforts to develop L-lactic acid as a chiral auxiliary for the dynamic resolution, we have recently found successful results with ethyl L-lactate. We herein report ethyl L-lactate-mediated dynamickinetic resolution of α-bromo esters for the asymmetric preparation of α-amino acid derivatives. Treatment of racemic α-bromo-α-phenylacetic
L-Tartaric Acid as a New Chiral Auxiliary for Asymmetric Synthesis of Piperazinones, Morpholinones, Dihydroquinoxalinones and Dihydrobenzoxazinones
作者:Yelim Kim、Kon Ji Park、Yong Sun Park
DOI:10.5012/bkcs.2012.33.11.3853
日期:2012.11.20
2012, Accepted August 10, 2012Key Words : Dynamic resolution, Nucleophilic substitution, Tartaricacid, Chiralauxiliary, Asymmetric syn-thesisDynamic resolution of α-haloacyl compounds in nucleo-philic substitution has been recently developed as an asym-metric synthetic method for α-substituted carboxylic acids.