Carbon Dioxide-Mediated C(<i>sp</i><sup>2</sup>)–H Arylation of Primary and Secondary Benzylamines
作者:Mohit Kapoor、Pratibha Chand-Thakuri、Michael C. Young
DOI:10.1021/jacs.9b03375
日期:2019.5.15
the pharmacological importance of ortho-arylbenzylamines, however, effective ortho-C-C bond formation of free primary and secondarybenzylamines using PdII remains an outstanding challenge. Presented herein is a new strategy for constructing ortho-arylated primary and secondarybenzylamines mediated by carbon dioxide (CO2). The use of CO2 with Pd is critical to allowing this transformation to proceed
通过过渡金属催化的 CH 活化形成 CC 键已成为快速制造新键的重要策略。然而,尽管邻芳基苄胺具有药理学重要性,但使用 PdII 形成游离伯胺和仲苄胺的有效邻 CC 键仍然是一个突出的挑战。本文提出了一种用于构建由二氧化碳 (CO2) 介导的邻位芳基化伯和仲苄胺的新策略。CO2 与 Pd 的使用对于允许这种转化在相对温和的条件下进行至关重要,机械研究表明它 (CO2) 直接参与速率决定步骤。此外,较温和的温度提供了无需脱保护即可直接使用或加工的游离胺产品。
Reactions of Et<sub>3</sub>ZnLi with Ketones: Electronic and Steric Effects<sup>1</sup>
作者:Curtis A. Musser、Herman G. Richey
DOI:10.1021/jo000630j
日期:2000.11.1
Toluene solutions of composition Et3ZnLi react rapidly with aldehydes and ketones to form addition products. Et3ZnNa and Et3ZnK solutions react readily with the same substrates although metalation, as well as addition, is significant with substrates having alpha -hydrogens. The Et3ZnM solutions react with 2-cyclohexenone to give mainly the 1,4-addition product. Relative rates of addition of Et3ZnLi to substituted acetophenones give a Hammett rho of 2.78. Addition of Et3ZnLi to acetophenone is sf owed significantly by alpha and ortho methyl substituents; relative rates of addition to acetophenone, o-methylacetophenone, and tert-butyl phenyl ketone are 1.00, 0.012, and 0.003.
Access to “Friedel–Crafts-Restricted” <i>tert</i>-Alkyl Aromatics by Activation/Methylation of Tertiary Benzylic Alcohols
作者:Joshua A. Hartsel、Derek T. Craft、Qiao-Hong Chen、Ming Ma、Paul R. Carlier
DOI:10.1021/jo202371c
日期:2012.4.6
Herein we describe a two-step protocol to prepare m-tert-alkylbenzenes. The appropriate tertiary benzylic alcohols are activated with SOCl2 or concentrated HCl and then treated with trimethylaluminum, affording the desired products in 68-97% yields (22 examples). This reaction sequence is successful in the presence of a variety of functional groups, including acid-sensitive and Lewis-basic groups. In addition to t-Bu groups, 1,1-dimethylpropyl and 1-ethyl-1-methylpropyl groups can also be installed using this method.
One-Pot C–H Arylation/Lactamization Cascade Reaction of Free Benzylamines
作者:Pratibha Chand-Thakuri、Vinod G. Landge、Mohit Kapoor、Michael C. Young
DOI:10.1021/acs.joc.0c00542
日期:2020.5.15
ortho-arylation of benzylamines followed by in situ lactamization. This cascade sequence is enabled by the use of 2-iodobenzoates, which facilitates C-H arylation from the free amine under conditions that typically require an improved directing group approach. This reaction is characterized by a broad substrate scope with good functional group tolerance. The need for an ester versus carboxylic acid-functionalized
Alkyl groups in trialkylboranes were successfully transferred to carbonylcompounds in the presence of the platinum cathode and copper anode by electrochemical method. The new, mild electrochemical alkyl transfer reaction produced various substituted alcohols in good yields.