Pipecolic Acid-Catalyzed Direct Asymmetric Mannich Reactions
摘要:
Mannich reactions between aldehydes and N-p-methoxyphenyl-protected alpha-imino ethyl glyoxylate have been performed using (S)-pipecolic acid as catalyst. The reactions give both syn- and ant products (dr = 1.4-2:1) with high enantioselectivities (> 98% ee). In contrast, (S)proline-catalyzed reactions give mainly syn-products with high enantioselectivities. Computational studies reveal that the energetic preference between the transition structures involving the s-cis-enamine and the s-trans-enamine is smaller for the pipecolic acid as compared to proline, yielding the (2S,3R)-anti and the (2S,3S)-syn Mannich product in nearly equal amounts.
Direct organocatalytic asymmetric Mannich-type reactions in aqueous media: one-pot Mannich-allylation reactions
作者:Armando Córdova、Carlos F Barbas
DOI:10.1016/s0040-4039(03)00019-4
日期:2003.2
organocatalytic asymmetric Mannich-type reactions in aqueousmedia are demonstrated herein. l-Proline-catalyzed reactions in aqueousmedia to provide β-formyl substituted α-amino acid derivatives with excellent diastereoselectivities (dr up to 19:1, syn/anti) and high enantioselectivities (ee between 72 and >99%). These conditions provided for the development of novel one-potasymmetric syntheses of cyclic
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
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%.
Indoline-3-Carboxylic Acid Derived Organocatalysts for the anti-Mannich Reaction
作者:Jörg Pietruszka、Robert Christian Simon
DOI:10.1002/chem.201002130
日期:2010.12.27
Mannich type reactions of a preformed aldimine with various carbonyl compounds were investigated with a series of functionalised indoline derivatives as catalysts: indoline‐3‐carboxylic acid, the diphenylcarbinol analogue and O‐protected silyl ether analogues. All compounds were readily prepared in enantiopure form by using an enzymatic kinetic resolution as a key step (E≫100). The alcohol and ether