Catalytic Enantioselective Synthesis of Bicyclic Lactam <i>N</i>
,<i>S</i>
-Acetals in One Pot by Cascade Transformations
作者:Kaiheng Zhang、Luca Deiana、Erik Svensson Grape、A. Ken Inge、Armando Córdova
DOI:10.1002/ejoc.201900923
日期:2019.8.7
A versatile strategy for the enantioselective synthesis of bicycliclactam N,S-acetals by one-pot cascade transformations is disclosed. The transformation of readily available substrates is promote ...
general efficient organocatalyst suitable for various types of anti-Mannichreactions and broad substrate scope. Excellent results (up to 98% yield, >99% ee and >99 : 1 dr) were achieved with 5 mol% catalyst load. Sulfones with ortho substituents or very strong withdrawing groups on the aromatic ring, which have been regarded as challenging substrates in the direct anti-Mannichreactions of aldehydes with
The novel pyrrolidine-based aminosulfonamides (R,R)-2, (S)-3, and (S)-4 were designed and synthesized as organocatalysts and successfully applied for the anti-selective directasymmetricMannichreaction.
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,