Superelectrophilicity in Michael-Type Reactions: Water Addition to 4-Nitrobenzodifuroxan

Author:

Lakhdar Sami1,Berionni Guillaume2ORCID,Terrier François3

Affiliation:

1. Normandie Université, Laboratoire de Chimie Moléculaire et Thio-organique, CNRS-UMR 6507, ENSICAEN, Université de Caen Normandie

2. Department Chemie, Ludwig-Maximilians-Universität München

3. Institut Lavoisier de Versailles, UMR CNRS 8180

Abstract

Kinetic and thermodynamic measurements of the ease of covalent hydration of 4-nitrobenzodifuroxan (NBDF) to give the corresponding hydroxy adduct has been carried out over a large pH range of 0.82–12.23 in aqueous solution. A most important result is that water is the sole efficient nucleophile contributing to the hydration of this peculiar nitroolefin in the pH range 4–8. Based on this finding as well as a pK a H2O value of 2.85 for the complexation process there is no doubt that the electrophilic character of NBDF falls in the domain of superelectrophilicity defined with reference to covalent nucleophilic additions to 4,6-dinitrobenzofuroxan (DNBF; pK a H2O = 3.75) and related heterocycles. This also corresponds to a positioning of NBDF at the top of the electrophilicity scale E introduced by Mayr to describe the feasibility of nucleophilic-electrophilic combinations. Returning to the hydration of the series of activated olefins, it has been possible to expand the domain of reactivity of Michael acceptors by six orders of magnitude, going from benzylidenemalonitrile (pK a H2O = 10.70; E = –9.42) to the para-nitro-substituted benzylidene Meldrum’ s acid (pK a H2O = 3.46; E = –5.49). The positioning of these olefins on the pK a scale shows that not only 4-nitrobenzodifuroxan but also the unsubstituted Meldrum’s acid are located in the superelectrophilic region.

Publisher

Georg Thieme Verlag KG

Subject

Organic Chemistry,Catalysis

Cited by 1 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

1. Aromatic Substitution;Organic Reaction Mechanisms Series;2020-07-24

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3