Highly Regioselective Synthesis of 1-Acyl-5-hydroxypyrazolines or Synthesis of 3,5-Disubstituted Pyrazoles from (E)-β-Chlorovinyl Ketones and Benzohydrazides or Hydrazine Hydrate
摘要:
Highly regioselective synthesis of 1-acyl-5-hydroxypyrazolines or synthesis of 3,5-disubstituted pyrazoles have been achieved through the cyclocondensation of (E)/beta-chlorovinyl ketones with benzohydrazides/hydrazine hydrate under extremely mild reaction conditions. The mechanistic studies showed that diverse electrophilic pathways of (E)-beta-chlorovinyl ketones could be observed by using different nucelophilic species. Moreover, the utility of the tandem reaction is further illustrated by the concise synthesis of 1-acyl-pyrazole and 3-pentyl-5-phenyl-1H-pyrazole.
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
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
Ambivalent Reactivity Modes of β-Chlorovinyl Ketones: Electrophilic Lithium [3]Cumulenolates from Soft Vinyl Enolization Strategy
作者:Hun Young Kim、Edward Oscar Rooney、Raymond Phillip Meury、Kyungsoo Oh
DOI:10.1002/anie.201302750
日期:2013.7.29
Soft spot: The softvinylenolization of (E)‐β‐chlorovinyl ketones results in the in situ generation of electrophiliclithium [3]cumulenolates, which react with nucleophiles such as another lithium [3]cumulenolate to stereoselectively form vinyl allenones. They can also react with ketimine esters to give 3‐methylenepyrrolidines.
A Soft Vinyl Enolization Approach to α-Acylvinyl Anions: Direct Aldol/Aldol Condensation Reactions of (<i>E</i>)-β-Chlorovinyl Ketones
作者:Hun Young Kim、Jian-Yuan Li、Kyungsoo Oh
DOI:10.1002/anie.201209876
日期:2013.3.25
Synthesizing the synthons: The development of α‐acylvinyl anion synthons has been achieved using direct α‐vinyl enolization of α,β‐unsaturated ketones under mild reaction conditions. The synthetic utility of such synthons has been demonstrated in intermolecular aldol and aldol condensation reactions, which provide synthetically useful allenyl ketone and enyne derivatives.
Herein, a palladium-catalyzed diastereoselective dearomatization/cross-coupling cyclization reaction between N-arylacyl indoles and (E)-β-chlorovinyl ketones is reported. Through this cyclization/cycloisomerization cascade, a series of furan-containing indolines were obtained in yields up to 95%. The reaction features readily accessible starting materials, benzyl Pd(II)-catalyzed cycloisomerization
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。