Highly Enantioselective Hydrogenation of Styrenes Directed by 2′-Hydroxyl Groups
摘要:
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.
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。
Nickel catalyzed intramolecular oxidative coupling: synthesis of 3-aryl benzofurans
transition metal-catalyzed reactions. Herein we have developed nickel-catalyzed synthesis of 3-aryl benzofurans from ortho-alkenyl phenols via intramolecular dehydrogenative coupling. Notably, simple O2 gas served as an oxidant, without using any sacrificial hydrogen acceptor. The strategy enabled the synthesis of 3-aryl benzofurans in good to excellent yields.
最近的研究集中在过渡金属催化的反应上。在此,我们开发了通过分子内脱氢偶联从邻-烯基酚中镍催化合成 3-芳基苯并呋喃。值得注意的是,简单的 O 2气体用作氧化剂,没有使用任何牺牲的氢受体。该策略能够以良好至优异的产率合成 3-芳基苯并呋喃。
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。
Substituent-Controlled Copper-Catalyzed Trifluoromethylation of 1,7-Dienes: Synthesis of Mono- and Bis-trifluoromethylated Benzoxepines
A copper-catalyzed trifluoromethylation of benzene-linked 1,7-dienes with 1-trifluoromethyl-1,2-benziodoxole via a radical cascade cyclization process for the synthesis of mono- and bis-trifluoromethylated benzoxepines is developed. The selectivity depends on substituents on the double bond of the allyl group in 1,7-dienes. The large-scale operation and late-stage functionalization of bioactive molecules