Potassium Base‐Catalyzed Michael Additions of Allylic Alcohols to α,β‐Unsaturated Amides: Scope and Mechanistic Insights
作者:Masahiro Sai、Hiroaki Kurouchi
DOI:10.1002/adsc.202100272
日期:——
We report herein the first KHMDS-catalyzed Michaeladditions of allylic alcohols to α,β-unsaturated amides through allylic isomerization. The reaction proceeds smoothly in the presence of only 5 mol% of KHMDS to afford a variety of 1,5-ketoamides in high yields. Mechanistic investigations, including experimental and computational studies, reveal that the KHMDS-catalyzed in-situ generation of the enolate
Dehydration in water: frustrated Lewis pairs directly catalyzed allylization of electron-rich arenes and allyl alcohols
作者:Hua Zhang、Xiao-Yu Zhan、Yu Dong、Jian Yang、Shuai He、Zhi-Chuan Shi、Xiao-Mei Zhang、Ji-Yu Wang
DOI:10.1039/d0ra02912b
日期:——
A frustratedLewispair (FLP)-catalyzed allylation of allyl alcohols with electron-rich arenes has been developed. Interestingly, in this reaction, the electron-rich arenes and allyl alcohols are dehydrated in water. What's more, water was the sole byproduct of the reaction. In this protocol, various allyl alcohols can be converted into allyl cations and attacked by the electron-rich arenes to form
一种受阻路易斯对(FLP)催化的烯丙醇与富电子芳烃的烯丙基化已经被开发出来。有趣的是,在该反应中,富电子芳烃和烯丙醇在水中脱水。更重要的是,水是反应的唯一副产物。在该方案中,各种烯丙醇可以转化为烯丙基阳离子并被富电子芳烃攻击形成芳基阳离子中间体。最后,芳基阳离子中间体去质子化得到1,3-二芳基丙烯。在该方案中,吲哚烯丙醇可以发生双分子闭环反应,可以顺利得到结构多样的四氢吲哚并[3,2- b ]咔唑。该反应对氧气不敏感,并且是在克级水平上进行的。
Transforming Racemic Compounds into Two New Enantioenriched Chiral Products via Intermediate Kinetic Resolution
作者:Jian Zhang、Mingyang Song、Weijun Tang、Dong Xue、Jianliang Xiao、Huaming Sun、Chao Wang
DOI:10.1021/acscatal.3c04599
日期:2023.12.1
Converting racemic compounds to enantioenriched products is an important and economic approach for accessing enantioenriched chiral molecules. A common method is kineticresolution. Herein, we present a mode of kineticresolution that transforms racemic compounds into enantioenriched products, in which the kineticresolution of reaction intermediates is the key. Catalyzed by a single Ru complex, racemic
将外消旋化合物转化为对映体富集的产物是获得对映体富集的手性分子的重要且经济的方法。一种常见的方法是动力学拆分。在此,我们提出了一种将外消旋化合物转化为对映体富集产物的动力学拆分模式,其中反应中间体的动力学拆分是关键。在单一 Ru 配合物的催化下,外消旋烯丙醇与甘氨酸衍生的席夫碱反应,生成两种手性化合物,即 δ-羰基产物和 δ-羟基变体,具有良好的产率和立体选择性(高达 >20: 1 dr,99% ee,920 s 因子)。机理研究表明,反应中存在多个氢转移事件:脱氢偶联过程,产生一对外消旋中间体,以及转移氢化驱动的动力学拆分过程,分解中间体,同时在催化剂上释放 H 2 。
Rapid Access to Densely Functionalized Cyclopentenyl Sulfoximines through a Sc-Catalyzed Aza-Piancatelli Reaction
Sulfoximines make up a class of compounds of growing interest for crop science and medicinal chemistry, but methods for directly incorporating them into complex molecular scaffolds are lacking. Here we report a scandium-catalyzed variant of the aza-Piancatelli cyclization that can directly incorporate sulfoximines as nucleophiles rather than the classical aniline substrates. Starting from 2-furylcarbinols