A facile and convenient sequential homobimetallic catalytic approach towards β-methylstyrenes. A one-pot Stille cross-coupling/isomerization strategy
作者:Sebastián O. Simonetti、Enrique L. Larghi、Teodoro S. Kaufman
DOI:10.1039/c4ob00604f
日期:——
A one-pot approach towards β-methylstyrenes is reported. The transformation involves a Stille cross-coupling reaction of aryl halides with allyltributylstannane, followed by an in situ Pd-catalyzed double bond conjugative migration.
Cobalt-Catalyzed Allylic C(sp<sup>3</sup>)–H Carboxylation with CO<sub>2</sub>
作者:Kenichi Michigami、Tsuyoshi Mita、Yoshihiro Sato
DOI:10.1021/jacs.7b02775
日期:2017.5.3
tolerability, so that selective addition to CO2 occurred in the presence of other carbonyl groups such as amide, ester, and ketone. Since styrylacetic acidderivatives can be readily converted into optically active γ-butyrolactones through Sharpless asymmetric dihydroxylation, this allylic C(sp3)-H carboxylation showcases a facile synthesis of γ-butyrolactones from simple allylarenes via short steps.
借助 Co/Xantphos 复合物开发了末端烯烃的烯丙基 C(sp3)-H 键与 CO2 的催化羧化。广泛的烯丙基芳烃和 1,4-二烯以中等至高产率成功转化为线性苯乙烯乙酸和六-3,5-二烯酸衍生物,并具有出色的区域选择性。羧化显示出显着的官能团耐受性,因此在其他羰基(如酰胺、酯和酮)存在的情况下,会发生选择性加成到 CO2 中。由于苯乙烯乙酸衍生物可以通过 Sharpless 不对称二羟基化很容易地转化为光学活性的 γ-丁内酯,这种烯丙基 C(sp3)-H 羧化展示了从简单的烯丙基芳烃通过短步骤轻松合成 γ-丁内酯。
Gold‐Catalyzed 1,2‐Diarylation of Alkenes
作者:Chetan C. Chintawar、Amit K. Yadav、Nitin T. Patil
DOI:10.1002/anie.202002141
日期:2020.7.13
Herein, we disclose the gold‐catalyzed 1,2‐diarylation of alkenes through the interplay of ligand‐enabled AuI/AuIII catalysis with the idiosyncratic π‐activation mode of gold complexes. Unlike the classical migratory‐insertion‐based approach to 1,2‐diarylation, the present approach not only circumvents the formation of direct Ar−Ar′ coupling and Heck‐type side products but more intriguingly demonstrates
本文中,我们通过配体使能的Au I / Au III催化与金配合物的特质π活化模式的相互作用揭示了金的烯烃1,2-二芳基化反应。与经典的基于迁移插入的方法进行1,2-二芳基化不同,本方法不仅规避了直接Ar-Ar'偶联和Heck型副产物的形成,而且更有趣地证明了其反应性和选择性与先前已知的互补金属催化(Pd,Ni或Cu)。对机理进行详细研究的结果表明,由于芳基烯烃具有非清白的性质,芳基碘化物向Au I络合物的氧化加成是限速步骤。
Säurekatalysierte Umlagerung von 4-Allyl-cyclohex-2-en-1-olen; Beispiele für ladungskontrollierte [3<i>s</i>, 4<i>s</i>]-Umlagerungen von cyclischen Allylkationen
The acid-catalysedrearrangement of the cyclohex-2-en-1-ols 15, d3-15, 16, 17 and 19, the cyclohexa-2,5-dien-1-ols 20 and 21, and also the allyl alcohols 22 and 23 (Scheme 3), using 98-percent sulfuric acid/acetic anhydride 1:99 at room temperature, was investigated. From the rearrangement of 4-allyl-4-phenyl-cyclohex-2-en-1-ol (15), with reaction times greater than 2 hours a single product is obtained
的酸催化的重排的环己-2-烯-1-醇15,d 3 - 15,16,17和19中,环己-2,5-二烯-1-醇20和21,并且还烯丙基醇在室温下使用98%的硫酸/乙酸酐(1:99)研究了图22和23(方案3)。通过4-烯丙基-4-苯基-环己-2-烯-1-醇的重排(15),反应时间大于2小时,可以得到单一产物4-烯丙基-联苯(50),产率为33% (方案9)。低于2小时乙酸反应时间53从隔离了15个,可以将其转换为50个。2',3',3'-d 3 -15在Ac 2 O / H 2 SO 4中的反应导致1',1',2'-d 3 -50(方案11)。4-烯丙基-4-甲基-环己-2-烯-1-醇的重排(16)(方案14)产生39%的相应乙酸盐60和30%的4-烯丙基-甲苯(6)结果是在反应条件下重排60。这些重排均为[3s,4s]-σ反应,其通过环己烯基阳离子a进行(方案12,R = C 6 H 5,CH
Generation of Aryl and Heteroaryl Magnesium Reagents in Toluene by Br/Mg or Cl/Mg Exchange
作者:Dorothée S. Ziegler、Konstantin Karaghiosoff、Paul Knochel
DOI:10.1002/anie.201802123
日期:2018.5.28
very fast Br/Mgexchange with aryl and heteroaryl bromides, producing aryl and heteroaryl magnesium alkoxides (ArMgOR⋅LiOR) in toluene. These Grignard reagents react with a broad range of electrophiles, including aldehydes, ketones, allyl bromides, acyl chlorides, epoxides, and aziridines, in good yields. Remarkably, the related reagent sBu2Mg⋅2 LiOR (R=2‐ethylhexyl) undergoes Cl/Mgexchange with various