亚磺酸的不同加成模式被开发用于烯酮的化学发散磺酰化,其中烯酮的炔部分的离子磺酰化是通过盐控制的顺式加成途径实现的。烯烃部分的自由基磺酰化也提供了立体定义的磺酰化烯烃。还探索了Ti(O i -Pr) 4催化的 ( E )-β-氯乙烯基酮的 α-乙烯基醛醇缩合,然后进行化学发散磺酰化的一锅串联序列,从而可以轻松获得高度取代的二烯和埃尼斯。
在此,报道了N-芳酰基吲哚和( E )-β-氯乙烯基酮之间的钯催化的非对映选择性脱芳构化/交叉偶联环化反应。通过这种环化/环异构化级联,获得了一系列含呋喃二氢吲哚,产率高达 95%。该反应具有易于获得的起始原料、苄基Pd(II)催化的( E )-β-氯乙烯基酮环异构化、三键和双杂环的顺序形成以及优异的非对映选择性。更重要的是,卡宾-仲苄基迁移插入被证明是顺序环化中的关键过程。
Divergent Halogenation Pathways of 2,2‐Dichlorobut‐3‐yn‐1‐ols to 3‐Chloro‐4‐Iodofurans and α‐Chloro‐γ‐Iodoallenes: Electrophilic versus Pd(II)‐Catalyzed Halogenation Strategies
作者:Mohamed Ahmed Abozeid、Hun Young Kim、Kyungsoo Oh
DOI:10.1002/adsc.202001033
日期:2020.12.8
Divergent halogenation pathways of 2,2‐dichlorobut‐3‐yn‐1‐ols have been developed to give 3,4‐dihalofurans and 1,3‐dihaloallenyl ketones in good to excellent yields. Thus, the readily accessible 2,2‐dichlorobut‐3‐yn‐1‐ols were treated with the electrophilic halogen source to provide the 1,3‐dihalogen‐substituted allenyl ketones, whereas the use of Pd(II) catalyst promoted the oxypalladation followed
Studies on Elimination Pathways of β-Halovinyl Ketones Leading to Allenyl and Propargyl Ketones and Furans under the Action of Mild Bases
作者:Hun Young Kim、Jian-Yuan Li、Kyungsoo Oh
DOI:10.1021/jo302253c
日期:2012.12.21
stereochemically defined β-halovinyl ketones has been investigated using a mild base, NEt3, leading to the formation of allenyl ketones and propargyl ketones. A preferential α-vinyl enolization of (E)-β-chlorovinyl ketones has been observed where a nonplanar s-cis conformation is proposed as a dominant conformation as opposed to a planar s-cis conformation of (Z)-β-chlorovinyl ketones. Other eliminative pathways
Synthesis of Polysubstituted 2<i>H</i>
-Pyran-2-ones or Phenols via One-Pot Reaction of (<i>E</i>
)-<i>β</i>
-Chlorovinyl Ketones and Electron-Withdrawing Group Substituted Acetates or <i>β</i>
-Diketones
作者:Youchi Zhang、Jingli Zhang、Ye Yuan、Liran Liu、Bifeng Chen、Taolei Sun
DOI:10.1002/ejoc.202000199
日期:2020.4.7
This paper describes a facile one‐potsynthesis of highly functionalized 2H‐pyran‐2‐ones and a regiospecific construction of 3,5‐disubstituted phenols via base‐promoted annulation of readily available β‐chlorovinyl ketones with various active methylene compounds. The detailed experimental studies demonstrated that versatile electrophilic pathways of β‐chlorovinyl ketones could be observed by using
1,3-Dienones and 2<i>H</i>-Pyran-2-ones from Soft α-Vinyl Enolization of β-Chlorovinyl Ketones: Defined Roles of Brönsted and Lewis Base
作者:Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.5b03265
日期:2015.12.18
The eliminative reaction pathways of (E)-β-chlorovinyl ketones were investigated in the presence of both Brönsted and Lewis bases. The Brönsted base, Et3N, effected the soft α-vinyl enolization of (E)-β-chlorovinyl ketones to [3]cumulenol intermediates; in turn, a catalytic amount of Lewis base, PPh3, initiated isomerization to provide 1,3-dienones in high yields. The introduction of a carbon-based
在布朗斯台德碱和路易斯碱的存在下研究了(E)-β-氯乙烯基酮的消除反应途径。布朗斯台德碱Et 3 N影响了(E)-β-氯乙烯基酮向[3]异丙苯三酚中间体的软α-乙烯基烯醇化作用。进而,催化量的路易斯碱PPh 3引发了异构化反应,以高收率提供了1,3-二烯酮。将碳基亲核试剂引入反应混合物中,可在一锅中高效合成2 H -pyran-2-one,其中碳基亲核试剂是由额外等价的布朗斯台德碱Et 3生成的N,攻击亲电的[3]枯烯酚中间体以起始环化,得到2 H-吡喃-2-酮。
A facile synthesis of 3,4-dimercaptofurans via sulfenylation of (E)-β-chlorovinyl ketones and 1,2-sulfur migration
作者:E. Song、H. Y. Kim、K. Oh
DOI:10.1039/c6ob02772e
日期:——
The one-pot sulfenylation of (E)-β-chlorovinyl ketones was investigated under soft α-vinyl enolization conditions. Modulating the nature of nucleophilic species using a “hard” base the regioselective formation of α,γ-dithio-allenyl ketones has been achieved, where the thermodynamic control was mimicked by the presence of Et3N·HCl. The sulfenylated products, α,γ-dithio-allenyl and α,α-dithio-propargyl