A Highly Enantioselective Route to Either Enantiomer of Both α- and β-Amino Acid Derivatives
作者:Armando Córdova、Shin-ichi Watanabe、Fujie Tanaka、Wolfgang Notz、Carlos F. Barbas
DOI:10.1021/ja017833p
日期:2002.3.1
α-amino acids and derivatives in high yield and stereoselectivity. Six of the seven aldehydes studied yielded products with ee values of 99% or greater. The diastereoselectivity of the reaction increased with the bulkiness of the substituents of the aldehyde donor in the order R = Me < Et < i-Pr < n-Pent. In five of the cases studied, excellent syn stereoselectivities were achieved. In addition, the corresponding
这份报告描述了在催化不对称曼尼希型反应中前所未有地使用未改性的醛作为供体。N-PMP 保护的 α-亚氨基乙醛酸乙酯与未修饰的脂肪醛的脯氨酸催化反应提供了一种通用且非常温和的进入 β-氨基和 α-氨基酸的对映异构体及其衍生物的高产率和立体选择性。研究的七种醛中的六种产生的产品 ee 值为 99% 或更高。反应的非对映选择性随着醛供体取代基的体积增加而增加,顺序为 R = Me < Et < i-Pr < n-Pent。在研究的五个案例中,实现了出色的顺式立体选择性。此外,相应的手性 β-氨基醛加合物可以很容易地转化为相应的氨基酸衍生物。最重要的是,
anti-Selective SMP-catalyzed direct asymmetric Mannich-type reactions: synthesis of functionalized amino acid derivatives
作者:Armando Córdova、Carlos F Barbas
DOI:10.1016/s0040-4039(02)01772-0
日期:2002.10
The first (S)-2-methoxymethylpyrrolidine (SMP)-catalyzed direct asymmetricMannich-type reactions of unmodified aldehydes with N-PMP-protected α-imino ethyl glyoxylate are described. The reaction proceeded in a highly anti-selective manner (dr up to 19:1) with enantioselectivities between 74 and 92%.
Enantioselective Organocatalytic Mannich Reactions with Autocatalysts and Their Mimics
作者:Xinbo Wang、Yongbo Zhang、Haibo Tan、Yanchao Wang、Peng Han、David Zhigang Wang
DOI:10.1021/jo902500b
日期:2010.4.2
The Mannich reactions previously extensively investigated with organocatalysis of L-proline and other related small molecules were reinvestigated with detailed stercochemical analysis of their autocatalysis pathways, through employment of both the products themselves and their close structural mimics as the catalysts. These organo-autocatalytic processes function as meaningful molecular models toward understanding the origin and maintenance of homochirality under biologically relevant conditions.
Organocatalysis in Ionic Liquids: Highly Efficient<scp>l</scp>-Proline-Catalyzed Direct Asymmetric Mannich Reactions Involving Ketone and Aldehyde Nucleophiles
作者:Carlos F. Barbas III、Naidu S. Chowdari、D. B. Ramachary
DOI:10.1055/s-2003-41483
日期:——
asymmetric Mannich reactions of N-PMP protected a-imino ethyl glyoxylate with various alde- hydes and ketones in ionic liquids afforded both a- and b-amino acid derivatives with excellent yields and enantioselectivities, providing facile product isolation, catalyst recycling, and signifi- cantly improved reaction rates, ca 4- to 50-fold. Three component Mannich reactionsinvolving other imines also
One-Pot Asymmetric Synthesis of β-Cyanohydroxymethyl α-Amino Acid Derivatives: Formation of Three Contiguous Stereogenic Centers
作者:Shin-ichi Watanabe、Armando Córdova、Fujie Tanaka、Carlos F. Barbas
DOI:10.1021/ol027048x
日期:2002.12.1
[reaction: see text] One-pot asymmetric Mannich-hydrocyanation reactions are described. Reaction of unmodified aldehydes with N-PMP-protected alpha-imino ethyl glyoxylate in the presence of catalyticamounts of L-proline followed by the addition of Et(2)AlCN provided highly enantiomericallypure beta-cyanohydroxymethyl alpha-amino acid derivatives possessing three contiguous stereogenic centers as