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
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.
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
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.