B(C
<sub>6</sub>
F
<sub>5</sub>
)
<sub>3</sub>
‐Catalyzed Hydroarylation of Aryl Alkynes for the Synthesis of 1,1‐Diaryl and Triaryl Substituted Alkenes
作者:Hui Chen、Liuzhou Gao、Xueting Liu、Guoqiang Wang、Shuhua Li
DOI:10.1002/ejoc.202101001
日期:2021.10.7
B(C6F5)3-catalyzed hydroarylation of both terminal and internal alkynes leads to 1,1-diaryl and triaryl substituted alkenes. A B(C6F5)3-phenol adduct mediated protonation mechanism is responsible for the formation of the related alkenes as well as the observed stereoselectivity.
B(C 6 F 5 ) 3 -催化的末端和内部炔烃的加氢芳基化产生1,1-二芳基和三芳基取代的烯烃。AB(C 6 F 5 ) 3 -苯酚加合物介导的质子化机制负责相关烯烃的形成以及观察到的立体选择性。
Palladium(II)-Catalyzed Direct Carboxylation of Alkenyl C–H Bonds with CO<sub>2</sub>
作者:Kota Sasano、Jun Takaya、Nobuharu Iwasawa
DOI:10.1021/ja405503y
日期:2013.7.31
Pd-catalyzed direct carboxylation of alkenyl C-H bonds with carbon dioxide was realized for the first time. Treatment of 2-hydroxystyrenes and a catalytic amount of Pd(OAc)2 with Cs2CO3 under atmospheric pressure of CO2 afforded corresponding coumarins in good yield. Furthermore, isolation of the key alkenylpalladium intermediate via C-H bond cleavage was achieved. The reaction was proposed to undergo
首次实现了 Pd 催化的烯基 CH 键与二氧化碳的直接羧化。在大气压 CO2 下用 Cs2CO3 处理 2-羟基苯乙烯和催化量的 Pd(OAc)2,以良好的收率得到相应的香豆素。此外,还实现了通过 CH 键断裂分离关键的烯基钯中间体。建议该反应进行烯基钯中间体与 CO2 的可逆亲核加成。
Visible-Light-Induced Difluoroalkylation of 1-(Allyloxy)-2-(1-arylvinyl)benzenes and 1-(1-Arylvinyl)-2-(vinyloxy)benzenes: Synthesis of Bis-Difluoroalkylated Benzoxepines and 2<i>H</i>-Chromenes
A novel visible-light-mediated difluoroalkylation of 1-(allyloxy)-2-(1-arylvinyl)benzenes and 1-(1-arylvinyl)-2-(vinyloxy)benzenes for the synthesis of bis-difluoroalkylated benzoxepines and 2H-chromenes is developed. This method features mild reaction conditions, good regioselectivity, a wide substrate scope, good functional-group compatibility, and late-stage modification. Preliminary mechanistic
1-(烯丙氧基)-2-(1-芳基乙烯基)苯和1-(1-芳基乙烯基)-2-(乙烯基氧基)苯的新型可见光介导二氟烷基化合成双-二氟烷基苯并氧杂环庚烷和2 H-开发了色烯。该方法具有反应条件温和、区域选择性好、底物范围广、官能团相容性好、后期修饰等特点。初步机理研究表明,CF 2 CO 2 Et 自由基的生成更容易与芳基的双键发生反应。
Highly Enantioselective Hydrogenation of Styrenes Directed by 2′-Hydroxyl Groups
作者:Xiang Wang、Anil Guram、Seb Caille、Jack Hu、J P. Preston、Michael Ronk、Shawn Walker
DOI:10.1021/ol200422p
日期:2011.4.1
A new synthetic strategy that turns styrene-type olefins into excellent substrates for Rh-catalyzed asymmetric hydrogenation by Installing a 2'-hydroxyl substituent is described. This methodology accommodates trisubstituted olefinic substrates in various E/Z mixtures, leading to valuable benzylic chiral compounds including (R)-tolterodine. It is also demonstrated that the 2'-hydroxyl groups could be readily removed in high yield without loss of ee from the products. Thus, this technology represents an attractive alternative to the Ir(P-N) catalyst system for the asymmetric hydrogenation of unfunctionalized olefins.
Rhodium(III)-Catalyzed<i>ortho</i>Alkenylation of<i>N</i>-Phenoxyacetamides with<i>N</i>-Tosylhydrazones or Diazoesters through CH Activation
作者:Fangdong Hu、Ying Xia、Fei Ye、Zhenxing Liu、Chen Ma、Yan Zhang、Jianbo Wang
DOI:10.1002/anie.201309650
日期:2014.1.27
A coupling reaction of N‐phenoxyacetamides with N‐tosylhydrazones or diazoestersthrough RhIII‐catalyzed CHactivation is reported. In this reaction, ortho‐alkenyl phenols were obtained in good yields and with excellent regio‐ and stereoselectivity. Rh–carbene migratory insertion is proposed as the key step in the reaction mechanism.