Regio- and Stereocontrol in the Michael-Initiated Ring-Closure Reactions of γ,δ-Epoxy-α,β-unsaturated Esters, Ketones, Sulfones, and Amides
摘要:
Organozincates or Grignard reagents in the presence of zinc catalysts undergo Michael initiated ring closure (MIRC) reactions with gamma,delta-epoxy-alpha,beta-enoates, enones, enesulfones, and enamides to afford 1,2,3-trisubstituted cyclopropanes. The direction of diastereoselectivity is solvent dependent for alkyl Grignard reagents reacting with epoxy enoates, ensulfones, and enamides but solvent independent for the enones. Excellent diastereoselectivity can be achieved for the epoxy enoates, enones, and ensulfones, while the enamides afford modest diastereoselectivity under optimal conditions. The MIRC reaction can be achieved with phenylmagnesium chloride and these substrates under reaction conditions designed to minimize biphenyl formation.
Copper‐Catalyzed Regio‐ and Stereoselective 1,6‐Conjugate Addition of Aza‐Heterocycles to 1‐Sulfonyl‐1,3‐dienes
作者:Subin Park、Hanseul Lee、Yunmi Lee
DOI:10.1002/adsc.201901299
日期:2020.2.6
sulfonyl‐functionalized allylic amines through the selective copper‐catalyzed aza‐1,6‐conjugate addition of heterocycles or arylamines to 1,4‐disubstituted‐1,3‐dienyl sulfones has been developed. This catalytic process is promoted by a combination of an easily prepared and sterically demanding N‐heterocycliccarbene‐based copper complex and KOt‐Bu under mild reaction conditions to provide a broad range of (E)‐allylic
通过选择性地将杂环或芳基胺选择性地铜催化的aza-1,6-共轭加成到1,4-二取代-1,3,2-二烯基砜上的一种高效,简单的合成新的,多功能的磺酰基官能化烯丙基胺的方法已经得到了应用。发达。在温和的反应条件下,由易于制备且空间上要求较高的N杂环卡宾基铜配合物和KO t Bu的组合促进了该催化过程,从而提供了具有优异区域和立体选择性的多种(E)烯丙基胺。 。
Iron-Catalyzed Regio- and Stereoselective Conjugate Addition of Aryl-Grignard Reagents to α,β,γ,δ-Unsaturated Sulfones and its Synthetic Application
iron‐catalyzed δ‐addition of aryl‐Grignard reagents to α,β,γ,δ‐unsaturated sulfones proceeded in a regio‐ and stereoselective manner to give cis‐4‐aryl‐2‐alkenyl sulfones. Allylic alkylation of the resultant products was performed without isomerization of the cis‐olefin to give cis‐4‐aryl‐1,1‐dialkyl‐2‐alkenyl sulfones, which upon intramolecular Friedel–Crafts reaction with aluminumchloride gave 1
Syntheses with sulfones XLV : stereoselective preparation of 1- benzenesulfonyl-1,3-dienes
作者:T. Cuvigny、C.Herve du Penhoat、M. Julia
DOI:10.1016/s0040-4020(01)82081-0
日期:1986.1
The stereoselective preparation of EE 1-benzenesulfonyl-1,3-dienes is described. Michael addition and Diels-Alder cycloaddition of these compounds are reported.