Two complementary classes of chiral boron enolates for adaptation to aldol additions to resin-bound aldehydes were studied: (i) the thioester-derived enolate 1 bearing chiral ligands on boron, and (ii) the chiral ketone-derived enolate 2. The viability of performing highly enantioselective, boron-mediated, aldolreactions was demonstrated by the preparation of resin-bound adducts 15 (91% ee) and 21
Catalytic, Asymmetric Mannich-type Reactions of <i>N</i>-Acylimino Esters: Reactivity, Diastereo- and Enantioselectivity, and Application to Synthesis of N-Acylated Amino Acid Derivatives
the synthesis of biologically important compounds were prepared using this novel catalytic asymmetricMannich-type reaction, and at the same time, absolute and relative stereochemical assignments were made. In addition, it has been revealed that alkyl vinyl ethers reacted with N-acylimino esters in the presence of a catalytic amount of the Cu(II) catalyst to give the corresponding Mannich-type adducts
在催化量的 Cu(OTf)(2)-手性二胺 3e 复合物存在下,N-酰基亚氨基酯与甲硅烷基烯醇醚反应以高产率和高对映选择性提供相应的曼尼希型加合物。各种衍生自酮的甲硅烷基烯醇醚以及酯和硫酯都能顺利反应。在α-取代的甲硅烷基烯醇醚(α-甲基或苄氧基)的反应中,以高产率和高非对映选择性和对映选择性获得了所需的顺式加合物。使用这种新型催化不对称曼尼希型反应制备了几种用于合成生物学上重要化合物的中间体,同时进行了绝对和相对立体化学分配。此外,已经表明,在催化量的 Cu(II) 催化剂存在下,烷基乙烯基醚与 N-酰基亚氨基酯反应,以高产率和高对映选择性得到相应的曼尼希型加合物。这是与烷基乙烯基醚催化不对称曼尼希型反应的第一个例子。基于Cu(II)-手性胺配合物的X射线晶体学分析、PM3计算和FT-IR分析等假设了反应机理、手性催化剂-亲电子配合物的结构以及这些催化不对称反应的过渡态. 最后,(1R,
Highly Modular Synthesis ofC1-Symmetric Aminosulfoximines and Their Use as Ligands in Copper-Catalyzed Asymmetric Mukaiyama-Aldol Reactions
作者:Martin Langner、Pauline Rémy、Carsten Bolm
DOI:10.1002/chem.200500497
日期:2005.10.21
The development of C1-symmetricaminosulfoximines, their highly modular synthesis, and their application in enantioselective copper-catalyzed Mukaiyama-type aldolreactions between pyruvates and enolsilanes is described. In this context, the influence of the ligand architecture as well as the optimization of the reaction conditions are discussed. In detail, the dependence of the catalyst efficiency
Facile Synthesis of 3,4-Dihydro<i>-</i>α-pyrones via Michael Reaction-O-Acylation Sequences
作者:Shû Kobayashi、Mitsuhiro Moriwaki
DOI:10.1055/s-1997-3229
日期:1997.5
3,4-Dihydro-α-pyrones were prepared in excellent yields with high stereoselectivities by the trityl salt-catalyzed Michael reaction and sequential intramolecular O-acylation of the intermediary silyl enol ethers using a mercury (II) salt (one-pot reaction).
Nucleophile Screening in Anion‐Binding Reissert‐Type Reactions of Quinolines with Chiral Tetrakis(triazole) Catalysts
作者:Qui‐Nhi Duong、Lukas Schifferer、Olga García Mancheño
DOI:10.1002/ejoc.201900566
日期:2019.9
A nucleophile screening based on Mayr's N‐scale for the triazole anion‐binding catalyzed enantioselective Reissert‐type dearomatization of quinolines is presented. This allows the identification of potential new reaction partners, which after re‐optimization provide synthetically valuable enantioenriched C2‐substituted dihydroquinolines.