Enantioselective Synthesis of α‐Aryl‐β
<sup>2</sup>
‐Amino‐Esters by Cooperative Isothiourea and Brønsted Acid Catalysis
作者:Feng Zhao、Chang Shu、Claire M. Young、Cameron Carpenter‐Warren、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1002/anie.202016220
日期:2021.5.17
The synthesis of α‐aryl‐β2‐amino esters through enantioselective aminomethylation of an arylacetic acid ester in high yields and enantioselectivity via cooperative isothiourea and Brønsted acid catalysis is demonstrated. The scope and limitations of this process are explored (25 examples, up to 94 % yield and 96:4 er), with applications to the synthesis of (S)‐Venlafaxine⋅HCl and (S)‐Nakinadine B.
证明了通过异硫脲和布朗斯台德酸协同催化,对芳基乙酸酯进行对映选择性氨甲基化,以高收率和对映选择性合成α-芳基-β 2 -氨基酯。探索了该过程的范围和局限性(25 个示例,产率高达 94% 和 96:4 er),并应用于 ( S )-文拉法辛·HCl 和 ( S )-Nakinadine B的合成。机理研究是一致的遵循 C(1)-烯醇化铵途径,而不是替代的动态动力学解析过程。对照研究表明 (i) 观察到催化剂和产物 er 之间存在线性效应;(ii)酰基铵离子可以用作预催化剂;(iii)可逆的异硫脲加成到原位生成的亚胺离子上,产生可用作生产性预催化剂的非循环中间体。
Stereodivergent Allylic Substitutions with Aryl Acetic Acid Esters by Synergistic Iridium and Lewis Base Catalysis
作者:Xingyu Jiang、Jason J. Beiger、John F. Hartwig
DOI:10.1021/jacs.6b11692
日期:2017.1.11
of all possible stereoisomers of a given chiral molecule bearing multiple stereocenters by a simple and unified method is a significant challenge in asymmetric catalysis. We report stereodivergent allylic substitutions with aryl aceticacid esters catalyzed synergistically by a metallacyclic iridium complex and benzotetramisole. Through permutations of the enantiomers of the two chiral catalysts, all
Traversing Steric Limitations by Cooperative Lewis Base/Palladium Catalysis: An Enantioselective Synthesis of α‐Branched Esters Using 2‐Substituted Allyl Electrophiles
作者:Kevin J. Schwarz、Colin M. Pearson、Gabriel A. Cintron‐Rosado、Peng Liu、Thomas N. Snaddon
DOI:10.1002/anie.201803277
日期:2018.6.25
Cooperative catalysis enables the direct enantioselective α‐allylation of linear prochiral esters with 2‐substituted allyl electrophiles. Critical to the successful development of the method was the recognition that metal‐centered reactivity and the source of enantiocontrol are independent. This feature is unique to simultaneous catalysis events and permits logical tuning of the supporting ligands
Enantioselective α-Benzylation of Acyclic Esters Using π-Extended Electrophiles
作者:Kevin J. Schwarz、Chao Yang、James W. B. Fyfe、Thomas N. Snaddon
DOI:10.1002/anie.201806742
日期:2018.9.10
esters is reported. This reaction proceeds via stereodefined C1‐ammonium enolate nucleophiles. Critical to its success was the identification of benzylic phosphate electrophiles, which were uniquely reactive. Alkylated products were obtained with very high levels of enantioselectivity, and this method has been applied toward the synthesis of the thrombin inhibitor DX‐9065a.
Pentafluorophenyl Group as Activating Group: Synthesis of α‐Deuterio Carboxylic Acid Derivatives via Et
<sub>3</sub>
N Catalyzed H/D Exchange
作者:Mengqi Peng、Hengzhao Li、Zixuan Qin、Junyu Li、Yanhao Sun、Xiaoxu Zhang、Ling Jiang、Hainam Do、Jie An
DOI:10.1002/adsc.202200258
日期:2022.7.5
We discovered that highly regioselective H/D exchange can be achieved on the α-position of the pentafluorophenyl (Pfp) ester using Et3N as the catalyst and D2O as the deuterium source. Our computational and experimental results showed that the Pfp group can significantly increase the acidity of the α-hydrogen of the ester. This mild reaction condition tolerated a variety of functional groups. 90%∼98%
我们发现,使用 Et 3 N 作为催化剂和 D 2 O 作为氘源,可以在五氟苯基 (Pfp) 酯的α位上实现高度区域选择性的 H/D 交换。我们的计算和实验结果表明,Pfp 基团可以显着增加酯的α-氢的酸度。这种温和的反应条件耐受多种官能团。用所有测试的 Pfp 酯获得了 90%~98% 的产率和 91%~98% 的氘掺入。利用Pfp酯的高反应活性,利用α合成了一系列有价值的α-氘代羧酸衍生物,包括除草剂、药物和药物中间体。-氘代Pfp酯作为前体。