Regio- and stereoselective intramolecular hydroalkoxylation of aromatic alkynols: an access to dihydroisobenzofurans under transition-metal-free conditions
Synthesis of dibenzocyclohepta[1,2-<i>a</i>]naphthalene derivatives from phenylacetaldehyde and alkynyl benzyl alcohols <i>via</i> sequential electrophilic addition and double Friedel–Crafts reactions
作者:Archana K. Sahu、Ramanjaneyulu Unnava、Bipin K. Behera、Anil K. Saikia
DOI:10.1039/d1ob00057h
日期:——
been developed for the synthesis of substituted 9H-dibenzo[3,4:6,7]-cyclohepta[1,2-a]naphthalenes from phenylacetaldehydes and ortho-alkynyl benzyl alcohols in the presence of a Lewis acid in moderate to good yields within a short reaction time. Interestingly, the reaction proceeds through a highly regioselective electrophilic addition followed by double Friedel–Crafts reaction to form uncommon dibenzo-fused
已经开发了一种简单的方法,用于在路易斯酸存在下,由苯乙醛和邻炔基苄基醇合成取代的9 H-二苯并[3,4:6,7]-环庚[1,2- a ]萘。在较短的反应时间内中度到良好的收率。有趣的是,该反应是通过高度区域选择性的亲电加成反应进行的,然后进行两次Friedel-Crafts反应,形成不常见的二苯并稠合的七元碳环。
Fused-Ring Formation by an Intramolecular “Cut-and-Sew” Reaction between Cyclobutanones and Alkynes
作者:Lin Deng、Likun Jin、Guangbin Dong
DOI:10.1002/anie.201712487
日期:2018.3.1
alkynes to construct cyclohexenone‐fused rings is described herein. The challenge arises from the need for selective coupling at the more sterically hindered proximal position, and can be addressed by using an electron‐rich, but less bulky, phosphine ligand. The control experiment and 13C‐labelling study suggest that the reaction may start with cleavage of the less hindered distal C−C bond of cyclobutanones
Synthesis of 2-Aryl Acetophenones via Hydrobromination and Oxy-isomerization of (<i>o</i>-Arylethynyl)benzyl Alcohols
作者:Tzu-Hsuan Kuan、Duen-Ren Hou
DOI:10.1021/acs.joc.1c00294
日期:2021.5.7
Hydrobromination and oxy-isomerization of (o-arylethynyl)benzyl alcohols to yield brominated aryl ketones were achieved with bromotrimethylsilane. The substrate scope suggested that vinyl carbocations, stabilized by the conjugated aryl groups, are the reaction intermediates. 1H-Isochromene was also detected by 1H NMR, and an isolated 1H-isochromene was converted to the product when retreated with TMSBr
用溴代三甲基硅烷实现了(邻-芳基乙炔基)苄醇的氢溴化和氧异构化,生成溴化的芳基酮。底物范围表明,通过共轭芳基稳定的乙烯基碳阳离子是反应中间体。还通过1 H NMR检测到1 H-异戊二烯,当用TMSBr处理时,分离出的1 H-异戊二烯转化为产物。1 H-异戊二烯的形成等同于6-内挖-环化,并与在基本条件下的相应反应形成对比,在该条件下,以5-外-挖为主导。
Assembly of 5<i>H</i>-dibenzo[<i>a</i>,<i>d</i>]cycloheptenes by a formal [5 + 2] annulation of <i>ortho</i>-aryl alkynyl benzyl alcohols with arenes
A new synthetic methodology for the synthesis of 5H-dibenzo[a,d]cycloheptenes from ortho-aryl alkynyl benzyl alcohols and arenes via a Tf2O-mediated formal [5 + 2] annulation reaction has been achieved. From this transformation, structurally diverse 5H-dibenzo[a,d]cycloheptenes were achieved in moderate to good yields. This transformation probably involves an intermolecular Friedel–Crafts-type alkylation
已经实现了一种新的合成方法,用于从邻-芳基炔基苯甲醇和芳烃通过Tf 2 O 介导的形式 [5 + 2] 环化反应合成 5 H-二苯并[ a , d ]环庚烯。通过这种转化,结构多样的 5 H-二苯并[ a , d ]环庚烯以中等至良好的产率获得。这种转化可能涉及分子间 Friedel-Crafts 型烷基化和随后在一个锅中进行的分子内 7 -endo-dig环化,突出了该协议的高效率、区域选择性和分步经济。
Selective cyclization of alkynols and alkynylamines catalyzed by potassium tert-butoxide
作者:Deng Yuan Li、Ke Ji Shi、Xiao Feng Mao、Zheng Le Zhao、Xin Yan Wu、Pei Nian Liu