三取代烯烃的立体选择性合成是有机化学中长期存在的挑战,因为三取代烯烃的 E 和 Z 异构体之间的能量差异很小(与 1,2-二取代烯烃相比)。1,1-二取代烯烃的过渡金属催化异构化可以作为三取代烯烃的替代方法,但由于与反应效率和立体选择性有关的问题,它仍然不发达。在这里,我们展示了一种新型钴催化剂可以克服这些挑战,为获得广泛的三取代烯烃提供有效和立体选择性的途径。该协议与单烯和二烯兼容,并表现出良好的官能团耐受性和可扩展性。而且,它已被证明是构建有机发光体和氘代三取代烯烃的有用工具。对该机制的初步研究表明,该反应涉及钴氢化物途径。该反应的高立体选择性归因于 π-π 堆积效应和底物和催化剂之间的空间位阻。
Mild, Efficient Friedel−Crafts Acylations from Carboxylic Acids Using Cyanuric Chloride and AlCl<sub>3</sub>
作者:Cyrous O. Kangani、Billy W. Day
DOI:10.1021/ol800752v
日期:2008.7.3
A mild method for Friedel-Craftsacylation with aromatic and aliphatic carboxylic acids using cyanuric chloride, pyridine, and AlCl(3) was developed. Both inter- and intramolecular acylations were achieved at room temperature in high yield and in very short reaction times.
Electrochemical oxidation-induced benzyl C H carbonylation for the synthesis of aromatic α-diketones
作者:Yu-Fang Tan、Yuan Chen、Rui-Xue Li、Zhi Guan、Yan-Hong He
DOI:10.1016/j.tetlet.2021.153593
日期:2022.1
direct carbonylation of benzyl CH bond for the synthesis of aromatic α-diketones is described. In this process, tetrabutylammonium iodide (nBu4NI) not only acts as an electrolyte, but its iodine anion is oxidized to an iodine radical at the anode, acting as a hydrogen atom transfer agent. The iodine radical extracts the benzyl hydrogen atom and causes the carbonylation of the benzyl position, where O2 in
描述了电化学氧化诱导的苄基 C H 键直接羰基化合成芳族 α-二酮。在这个过程中,四丁基碘化铵(n Bu 4 NI)不仅起到电解质的作用,而且其碘阴离子在阳极被氧化成碘自由基,起到氢原子转移剂的作用。碘自由基提取苄基氢原子并引起苄基位置的羰基化,其中空气中的O 2用作氧源。
β‐Arylation of Racemic Secondary Benzylic Alcohols to Access Enantioenriched β‐Arylated Alcohols
作者:Wang Miao、Jinyu Zhang、Yanyan Yang、Weijun Tang、Dong Xue、Jianliang Xiao、Huaming Sun、Chao Wang
DOI:10.1002/anie.202306015
日期:2023.7.24
catalyst, the first example of β-arylation of secondary alcohols with aryl bromides has been developed via borrowing hydrogen catalysis enabled by an MPV type hydrogen transfer process. In addition, the enantioconvergent version of the reaction has also been realized under the catalysis of Pd and Ru, allowing for the transformation of racemic secondary alcohols into enantioenriched chiral alcohols with good
Palladium/Silver-Cocatalyzed Tandem Reactions of Oxabenzonorbornadienes with Substituted Arylacetylenes: A Simple Method for the Preparation of 1,2-Diarylethanones and 1,2-Diarylacetylenes
作者:Jingchao Chen、Shanshan Liu、Yongyun Zhou、Sifeng Li、Chengyuan Lin、Zhaoxiang Bian、Baomin Fan
DOI:10.1021/acs.organomet.5b00551
日期:2015.9.14
The effective synthesis of 1,2-diarylethanones was achieved using palladium(II) acetate [Pd(OAc)(2)] and silver triflate (AgOTf) as cocatalysts from various oxabenzo-norbomadiene derivatives and substituted arylacetylenes via tandem reactions under mild conditions. Exploration of the oxabenzonorbomadiene substrates showed that the 1,2-diarylacetylenes were obtained from adjacent alkoxy substituted oxabenzonorbornadiene derivatives. Preliminary mechanistic studies indicate that the AgOTf served as an indispensable catalyst, and the mechanism of the tandem reaction was proposed.