Access to (<i>Z</i>)-β-Substituted Enamides from <i>N</i>1-H-1,2,3-Triazoles
作者:Tao Wang、Zongyuan Tang、Han Luo、Yi Tian、Mingchuan Xu、Qixing Lu、Baosheng Li
DOI:10.1021/acs.orglett.1c02087
日期:2021.8.20
A direct ring-opening/nucleophilic substitution reaction of N1-H-1,2,3-triazoles has been described. Divergent (Z)-β-halogen- or sulfonyl-substituted enamides could be stereospecifically synthesized in a tunable manner. This strategy might not only enable a new ring-opening method of N1-H-1,2,3-triazoles under nonmetal catalysis and mild reaction conditions but also offer a good opportunity to reliably
已经描述了N 1-H-1,2,3-三唑的直接开环/亲核取代反应。发散的 ( Z )-β-卤素或磺酰基取代的烯酰胺可以以可调的方式立体定向合成。这种策略不仅可以在非金属催化和温和的反应条件下实现N 1-H-1,2,3-三唑的新开环方法,而且还为可靠地获得多功能 ( Z )-β-取代的烯酰胺提供了良好的机会可用作进一步合成转化的合成前体。
Visible-Light-Driven [3 + 2]/[4 + 2] Annulation Reactions of Alkenes with <i>N</i>-Aminopyridinium Salts
The annulation reactions of benzoamidyl radicals with alkenes were realized under visible light irradiation with fac-Ir(ppy)3 as catalyst and N-aminopyridinium salts as benzoamidyl radical precursors. The reaction can deliver two distinct types of products: in the case of vinyl arenes, [3 + 2] annulation product dihydrooxazoles were yielded exclusively; when alkyl-substituted alkenes were used, on the
heteroaromatics by using benzamide radicals with free NH groups generated from N-amidopyridinium salts under visible-light irradiation. The new mode of activation of N-amidopyridinium salts proceeds efficiently under mild conditions to give various benzamide derivatives with free NH groups. In addition, oxazoline analogues, synthesized by the reaction with styrene, demonstrate a substantial range of prospective
Visible-light-induced Fe(iii)-promoted reduction amidation of 1,4,2-dioxazol-5-one
作者:Bosen Wang、Hao Li、Minmin Liu、Jiayi Lin、Chenglei Yang、Zhongkai Zhao、Dianjun Li、Jinhui Yang
DOI:10.1039/d4nj02305f
日期:——
under visible light to obtain aromatic/alkylsubstituted amides. The nitrogen radicals formed during this process undergo hydrogen atom transfer (HAT) to form amides through the proton provided by HBpin. This reaction eliminates the need for external chemical oxidants and expensive photocatalysts, and exhibits compatibility with various aryl/alkylsubstituted derivatives. This method has good prospects
Reaction of (1,ω)-<i>N</i>-Acylamino Alcohols with Lawesson's Reagent: Synthesis of Sulfur-Containing Heterocycles
作者:Takehiko Nishio
DOI:10.1021/jo961704n
日期:1997.2.1
Lawesson's reagent [LR: 2,4-bis(p-methoxyphenyl)-1,3,2,4-dithiaphosphetane 2,4-disulfide] is shown to be a valuable reagent for the ready access of sulfur-containing heterocycles: thiazolines 2 starting from the (1,2)-N-acylamino alcohols 1 and benzothiazines 14 from [2-(N-acylamino)phenyl]alkanols 12. Treatment of (1,2)-N-acylamino secondary alcohols 1a-p with LR gave the thiazolines 1a-p via direct conversion of the alcohols to the respective thiols, and the subsequent thionation of the amide carbonyl, followed by cyclization with the elimination of hydrogen sulfide. However, reaction of (1,2)-N-acylamino tertiary alcohols 1q-u with LR yielded the dehydration products 5-7 and 9. Treatment of [2-(N-acylamino)phenyl]alkanols 12a-f with a molar equivalent of LR yielded the 3,1-benzothiazines 14a-f. In this reaction, the [2-(N-acylamino)phenyl]alkanethiols 13a-e were isolated when the corresponding alcohols 12a-e were treated with 0.5 equiv of LR. Further thionation of 13c with LR also gave 3,1-benzothiazine 14c.