Synthesis of enantio- and diastereo-isomerically pure β- and γ-substituted glutamic acids via glycine condensation with activated olefins
作者:Yuri N. Belokon、Aleksandr G. Bulychev、Mikhail G. Ryzhov、Sergei V. Vitt、Andrei S. Batsanov、Yuri T. Struchkov、Vladimir I. Bakhmutov、Vasili M. Belikov
DOI:10.1039/p19860001865
日期:——
The glycine fragment in the nickel(II) complex formed from the Schiff base of glycine and (S)-o[(N-benzylprolyl)amino]benzophenone undergoes base-catalysed Michael addition in methanol in the presence of MeONa to the activatedolefins methyl acrylate, acrylonitrile, methyl methacrylate, acrolein, and methyl trans-cinnamate. Complexes of substituted (S)-glutamic acid or its derivatives were formed in
由甘氨酸的席夫碱和(S)-o [(N-苄基脯氨酰基)氨基]二苯甲酮形成的镍(II)配合物中的甘氨酸片段在MeONa存在下在甲醇中经历碱催化的迈克尔加成反应生成活化的烯烃甲基丙烯酸酯,丙烯腈,甲基丙烯酸甲酯,丙烯醛和反肉桂酸甲酯。取代的(S谷氨酸或其衍生物以良好的化学产率形成,并且在氨基酸部分的α-碳原子上几乎完全非对映异构。β-和γ-原子的非对映选择性不明显,但同分异构体配合物可通过色谱法轻松分离。用HCl水溶液裂解纯的非对映异构体,以良好的收率得到光学纯的谷氨酸,并再生了原始的手性试剂。通过1 H nmr光谱和相应原始配合物的晶体结构X射线分析,确定了氨基酸β-和γ-碳原子的构型。由三乙胺在甲醇中催化而向丙烯醛中添加,将仅生成1,4-加合物。由此获得的氨基酸可以转化为(S)-脯氨酸通过用NaBH 4还原。
Michael Addition Reactions between Chiral Ni(II) Complex of Glycine and 3-(<i>trans</i>-Enoyl)oxazolidin-2-ones. A Case of Electron Donor−Acceptor Attractive Interaction-Controlled Face Diastereoselectivity<sup>1</sup>
作者:Chaozhong Cai、Vadim A. Soloshonok、Victor J. Hruby
DOI:10.1021/jo0014865
日期:2001.2.1
noyl)oxazolidin-2-ones was found to depend exclusively on the steric bulk of the alkyl group on the starting Michael acceptor. In contrast, the face diastereoselectivity in the reactions of aromatic oxazolidin-2-ones with the Ni(II) complex of glycine was shown to be controlled predominantly by the electronic properties of the aryl ring. In particular, the additions of the Ni(II) complex of glycine
Chemoenzymatic Synthesis of Glutamic Acid Analogues: Substrate Specificity and Synthetic Applications of Branched Chain Aminotransferase from <i>Escherichia coli</i>
[GRAPHICS]A new route to alpha-keto acids is described, based on the ozonolysis of enol acetates obtained from alpha-substituted beta-keto esters. Escherichia coli branched chain aminotransferase (BCAT) activity toward a variety of substituted 2-oxoglutaric acids was demonstrated analytically. BCAT was shown to have a broad substrate spectrum, complementary to that of aspartate aminotransferase, and to offer access to a variety of glutamic acid analogues. The usefulness of BCAT was demonstrated through the synthesis of several 3- and 4-substituted derivatives.