在此,通过利用氟酰胺的不同活化模式,我们实现了具有可切换区域选择性的硝基烷烃的α-和δ-C(sp 3 )–H烷基化。Cu 催化作用使得以 N 为中心的自由基拦截远端以 C 为中心的自由基,从而偶联硝基烷烃和未活化的 δ-C-H 键。此外,氟酰胺原位生成的亚胺被硝基烷烃捕获,实现酰胺的α-C-H烷基化。这两种可扩展的协议都具有广泛的底物范围和良好的官能团耐受性。
PPh<sub>3</sub>
/Selectfluor-Mediated Transformation of Carboxylic Acids into Acid Anhydrides and Acyl Fluorides and Its Application in Amide and Ester Synthesis
An efficient synthesis of acid anhydrides or acyl fluorides mediated by PPh3/Selectfluor synstem is reported. Mechanistic studies show that the reaction proceeds through active species of acyloxyphosphonium ions, which can be quickly converted into the final products in situ by a second carboxylicacid or F–.
In this paper, we report the synthesis of N-acyltriazinedione via the unexpected O–N acyl rearrangement of acyloxytriazinone and its utility as an acylating reagent. N-Acyltriazinedione can be isolated by silica gel column chromatography and reacts with amines in the absence of any base to give the corresponding amides in good yields. Fullsize Image
To improve the efficiency of the photocatalytic decarbonylation of cyclopropenones, the effects of substituents on cyclopropenone were explored. A benzothiophene-substituted aminocyclopropenone exhibited significantly improved decarbonylation efficiency to produce the corresponding ynamine, which worked as a potent dehydration condensation agent. The benzothiophene derivative was applicable to the
Oxidative activation of dihydropyridine amides to reactive acyl donors
作者:Erik Daa Funder、Julie B. Trads、Kurt V. Gothelf
DOI:10.1039/c4ob01931h
日期:——
4-dihydropyridine (DHP) are activated by oxidation for acyltransfer to amines, alcohols and thiols. In the reduced form the DHP amide is stable towards reaction with amines at room temperature. However, upon oxidation with DDQ the acyl donor is activated via a proposed pyridinium intermediate. The activated intermediate reacts with various nucleophiles to give amides, esters, and thio-esters in moderate
A photocatalytic active alkyne generation reaction was developed using cyclopropenone as a starting reagent. Visible light-responsive photocatalysts induced cyclopropenonedecarbonylation. The resulting highly reactive alkyne could be used directly, without isolation, for further reactions, such as in a dehydration condensation reaction and alkyne–azide click chemistry.