Functionalized Alkenylzinc Reagents Bearing Carbonyl Groups: Preparation by Direct Metal Insertion and Reaction with Electrophiles
作者:Christoph Sämann、Matthias A. Schade、Shigeyuki Yamada、Paul Knochel
DOI:10.1002/anie.201302058
日期:2013.9.2
cyclic and acyclic alkenylzinc reagents bearing functional groups such as aldehyde, keto, and ester groups were readily prepared by either direct zinc insertion in the presence of LiCl or by magnesiuminsertion in the presence of LiCl and ZnCl2. Subsequent functionalization reactions, such as Negishi cross‐couplings, acylations, and allylations, furnished polyfunctional compounds in excellent yields
Stereoselective Preparation of Polyfunctional Alkenylindium(III) Halides and Their Cross-Coupling with Unsaturated Halides
作者:Zhi-Liang Shen、Paul Knochel
DOI:10.1002/chem.201500943
日期:2015.5.4
The directinsertion of indium powder to cycloalkenyl iodides in the presence of LiCl in THF allows the preparation of new highly functionalized cycloalkenylindium(III) derivatives. In addition, we discovered that, in contrast to many metal insertions to alkenyl iodides which proceed with a loss of stereochemistry, the insertion of In/LiCl to stereodefined (Z)‐ and (E)‐styryl iodides in THF proceeded
Photosensitized [2 + 2]-Cycloaddition of Complex Acceptor–Donor Combinations: A Regio/Diastereoselectivity Study
作者:Jens Lefarth、Axel G. Griesbeck
DOI:10.1021/acs.joc.2c00649
日期:2022.6.17
The photosensitized [2 + 2]-cycloaddition of chalcones, conjugated cyclopentenones, and cyclohexenones with electron-rich alkenes such as cyclic enolethers and polymethylated alkenes was investigated. While cyclic enones showed high regio- and stereoselectivity, acyclic enones resulted in a more complex product mixture containing dimers as well as four dominant regio- and diastereoisomers. This complex
Electrophilic 1,4-Addition of Carbon Dioxide and Aldehydes to Enones
作者:Shintaro Okumura、Kaoru Torii、Yasuhiro Uozumi
DOI:10.1021/acs.orglett.3c01675
日期:2023.7.21
An umpoled electrophilic 1,4-addition to enones was achieved under photocatalytic conditions. Various enones reacted with CO2 in the presence of an iridium photocatalyst and a benzimidazoline reductant under blue-light irradiation to give the corresponding γ-keto carboxylic acids. Aldehydes also coupled with enones under similar photocatalytic conditions to afford γ-keto alcohols (homoaldols) that
在光催化条件下实现了烯酮的未极化亲电 1,4-加成。各种烯酮在铱光催化剂和苯并咪唑啉还原剂存在下在蓝光照射下与CO 2反应生成相应的γ-酮基羧酸。醛还在类似的光催化条件下与烯酮偶联,得到γ-酮醇(高醛醇),通过共沸后处理将其转化为二氢呋喃和四氢呋喃。D 2 O 在 β 位的区域选择性氘掺入表明 1,4-加成是通过高烯醇阴离子发生的。
Selective Heck reaction of aryl bromides with cyclopent-2-en-1-one or cyclohex-2-en-1-one
作者:Yacoub Fall、Henri Doucet、Maurice Santelli
DOI:10.1016/j.tet.2008.11.006
日期:2009.1
The selective Heck reaction of cyclopent-2-en-1-one or cyclohex-2-en-1-one with aryl bromides gives a simple access to the corresponding 3-arylcycloalk-2-en-1-ones. The choice of the base was found to be crucial to avoid the formation of 3-arylcyclopentanones or 3-arylcyclohexanones as side-products. Using KF as base, DMF as solvent and Pd(OAc)(2) as catalyst, the target products were obtained in moderate to good yields with a variety of aryl bromides. Substituents such as fluoro, trifluoromethyl, acetyl, benzoyl, formyl, ester or nitrile on the aryl bromide are tolerated. Sterically congested aryl bromides or bromopyridines can also be employed. (C) 2008 Elsevier Ltd. All rights reserved.