Sequence‐Dependent Stereodivergent Allylic Alkylation/Fluorination of Acyclic Ketones
作者:Xi‐Jia Liu、Shicheng Jin、Wen‐Yun Zhang、Qiang‐Qiang Liu、Chao Zheng、Shu‐Li You
DOI:10.1002/anie.201912882
日期:2020.1.27
The stereodivergent iridium-catalyzed allylicalkylation and fluorination of acyclicketones is described. α-Pyridyl-α-fluoroketones with vicinal tertiary and quaternary stereocenters were obtained in moderate to excellent yields and stereoselectivities. Distinct from known stereodivergent synthesis, for which two different chiral catalysts are required in general, herein we report a sequence-dependent
A synthesis of chiral homoallylic nitriles by the iridium-catalyzed allylation of cyanoacetates followed by Krapcho demethoxycarbonylation has been developed. A wide range of homoallylic nitriles were obtained with a high enantioselectivity (>95–99% ee). These compounds are useful chiral building blocks because further synthetic elaboration starting from a nitrile or terminal alkene is possible.
Enantioselective α-Functionalization of 1,3-Dithianes by Iridium-Catalyzed Allylic Substitution
作者:Panpan Wang、Qian Jiang、Ruibo Zhao、Xingang Xie、Shouchu Tang、Xiaolei Wang
DOI:10.1021/acs.joc.0c01683
日期:2020.10.2
iridium-catalyzed asymmetric allylicsubstitution reaction with 2-alkoxy carbonyl-1,3-dithianes has been achieved with high regio- and enantioselectivities. The transformation provides a new method for the enantioselective α-functionalization of dithianes. The corresponding dithiane-containing products are easily converted into many other derivatives with high yields and enantioselectivities.
作者:Can-Can Bao、Dong-Song Zheng、Xiao Zhang、Shu-Li You
DOI:10.1021/acs.organomet.8b00762
日期:2018.12.24
N-Heterocyclic carbenes (NHCs) were found to be suitable ligands in Ir-catalyzed intermolecular allylic alkylation reaction. In the presence of a catalyst derived from [Ir(dncot)Cl]2 (dncot = dinaphthocyclooctatetraene) and triazolium salt L7, the alkylation products from the reaction of aryl allyl carbonates with sodium dialkyl malonates could be obtained in 85–99% yields favoring the formation of
发现N-杂环卡宾(NHC)是Ir催化的分子间烯丙基烷基化反应中的合适配体。在[Ir(dncot)Cl] 2(dncot =二萘环辛酸酯四烯)和三唑鎓盐L7衍生的催化剂存在下,芳基烯丙基碳酸酯与二烷基丙二酸钠的反应可得到烷基化产物,收率高达85-99%,形成支链产物(90/10→> 99/1 b / l)。此外,手性二氢异喹啉型NHC(DHIQ-NHC)(L8)已成功应用于Ir催化的不对称烯丙基烷基化反应中。对于广泛的底物,获得了优异的对映选择性和中等的区域选择性。
Stereodivergent Synthesis of α-Quaternary Serine and Cysteine Derivatives Containing Two Contiguous Stereogenic Centers via Synergistic Cu/Ir Catalysis
作者:Hui-Min Wu、Zongpeng Zhang、Fan Xiao、Liang Wei、Xiu-Qin Dong、Chun-Jiang Wang
DOI:10.1021/acs.orglett.0c01687
日期:2020.6.19
A stereodivergent preparation of α-quaternary serine/cysteinederivatives incorporating two adjacent stereogenic centers has been developed through Cu/Ir-catalyzed asymmetric allylation of 2-oxazoline-4-carboxylates and 2-thiazoline-4-carboxylates. Tuning the electronic effect is the key to enhancing the reactivity of 2-oxazoline-4-carboxylates and suppressing the undesired β-elimination. The salient