Telescoped Synthesis of Stereodefined Pyrrolidines
摘要:
Telescoped and one-pot olefination/asymmetric functionalization approaches to disubstituted pyrrolidines (dr up to 99:1, up to 99% ee) have been developed using commercially available tetramisole (0.1 to 5 mol %). Using OTMS-quinidine as the Lewis base gives preferential access to an anti-configured pyrrolidine in high enantioselectivity.
基于路易斯碱/布朗斯台德酸共催化的均烯丙基酸的硫醇化反应,开发了一种简便制备各种对映体富集的苯硫基取代的内酯的策略。探索了酸控制的区域发散环化(6-endo vs. 5-exo)和苯硫基取代的内酯的酸介导的立体选择性重排。进行了实验和计算研究以阐明区域选择性和对映选择性的起源。计算结果表明,CO和CS键的形成可能会同时发生,而不会形成通常认为的催化剂配位的硫鎓离子中间体,而且底物和SPh之间的潜在π-π堆积是对映确定步骤的重要因素。最后,
Cobalt-Catalyzed Diastereo- and Enantioselective Reductive Allyl Additions to Aldehydes with Allylic Alcohol Derivatives via Allyl Radical Intermediates
enantioenriched homoallylic alcohols with a remarkably broad scope of allyl groups that can be introduced. Mechanistic studies indicated that allyl radical intermediates were involved in this process. These new discoveries establish a new strategy for development of enantioselective transformations through capture of radicals by chiral Co complexes, pushing forward the frontier of Co complexes for enantioselective
stereoselective domino Rauhut–Currier/Michael addition process of 3-benzofuranyl vinyl ketones and 3-olefinic (7-aza)oxindoles can be realised via catalysis by a chiral bifunctional phosphine, furnishing the previously unreported direct asymmetric dearomative reaction of benzofuran substrates tethered to a carbonyl group in a formal [4+2] cycloaddition manner. An array of hydrodibenzofuran derivatives with dense
Rhodium-Catalyzed Asymmetric N−H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (−)-Chaetominine
作者:Yirong Zhou、Bernhard Breit
DOI:10.1002/chem.201705059
日期:2017.12.22
An unprecedented asymmetric N−H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo‐, regio‐, and enantioselectivities with broad functional
Disclosed is a practical method for efficiently producing an alcohol compound by hydrogenating an aldehyde by using a homogeneous copper catalyst which is an easily-available low-cost metal species. Specifically disclosed is a method for producing an alcohol compound, which is characterized in that a hydrogenation reaction of an aldehyde compound is performed in the presence of a homogeneous copper catalyst, a monophosphine compound and an alcohol selected from the group consisting of primary alcohols, secondary alcohols and mixtures of those.
Anti‐Markovnikov Hydroamination of Racemic Allylic Alcohols to Access Chiral γ‐Amino Alcohols
作者:Ruirui Xu、Kun Wang、Haoying Liu、Weijun Tang、Huaming Sun、Dong Xue、Jianliang Xiao、Chao Wang
DOI:10.1002/anie.202009754
日期:2020.12
ruthenium‐catalyzed formal anti‐Markovnikov hydroamination of allylicalcohols for the synthesis of chiral γ‐amino alcohols is presented. Proceeding via an asymmetric hydrogen‐borrowing process, the catalysis allows racemic secondary allylicalcohols to react with various amines, affording enantiomerically enriched chiral γ‐amino alcohols with broad substrate scope and excellent enantioselectivities (68 examples