Diisopropyl L-Malate as a New Chiral Auxiliary for Dynamic Kinetic Resolution of α-Bromo Esters and Asymmetric Syntheses of Aminoflavones and Dihydroquinoxalinones
作者:Kyoung-Hee Kang、Jung-In Jang、Seung-Bin Baek、Jung-Hee Ahn、Yong-Sun Park
DOI:10.5012/bkcs.2011.32.5.1741
日期:2011.5.20
auxiliary is, however, not well known in the area of asymmetric synthesis. We herein report the first example of L-malate-mediated dynamickineticresolution of αbromo esters in nucleophilicsubstitution with various arylamines. Treatment of diisopropyl L-malate with racemic α-bromo phenylacetic acid in the presence of DCC and DMAP provided α-bromo phenylacetate (αRS)-1 in 77% yield with about 50:50
(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