Formamide catalyzed activation of carboxylic acids – versatile and cost-efficient amidation and esterification
作者:Peter H. Huy、Christelle Mbouhom
DOI:10.1039/c9sc02126d
日期:——
A novel, broadly applicable method for amide C–N and ester C–O bond formation is presented based on formylpyrrolidine (FPyr) as a Lewis base catalyst. Herein, trichlorotriazine (TCT), which is the most cost-efficient reagent for OH-group activation, was employed in amounts of ≤40 mol% with respect to the starting material (100 mol%). The new approach is distinguished by excellent cost-efficiency, waste-balance
Photochemical generation of acyl and carbamoyl radicals using a nucleophilic organic catalyst: applications and mechanism thereof
作者:Eduardo de Pedro Beato、Daniele Mazzarella、Matteo Balletti、Paolo Melchiorre
DOI:10.1039/d0sc02313b
日期:——
detail a strategy that uses a commercially available nucleophilic organic catalyst to generate acyl and carbamoyl radicals upon activation of the corresponding chlorides and anhydrides via a nucleophilic acyl substitution path. The resulting nucleophilic radicals are then intercepted by a variety of electron-poor olefins in a Giese-type addition process. The chemistry requires low-energy photons (blue
A convergent approach to γ-carbonyl vinyl boronates
作者:Markus R. Heinrich、Lisa A. Sharp、Samir Z. Zard
DOI:10.1039/b502885j
日期:——
γ-Carbonyl vinyl boronates can be prepared by a visible light induced radical chain addition of an S-acyl dithiocarbonate (xanthate) to the pinacol ester of vinyl boronic acid, followed by treatment with base.
to the application of several alkyl organometallic nucleophiles (e.g., alkyl-zinc, boron, and magnesium) in asymmetric cross-couplings, more easily accessible alkylzirconocene reagents have received much less attention. Herein, we report a visible-light-induced, Ni-catalyzed, asymmetric cross-coupling of gem-borazirconocene alkenes with aryl and unactivated alkylhalides, furnishing a diverse series
equivalents of oxime 1 v and the reduction of the reaction time to 12 h, avoided the formation of adamantane. We then turned our attention to the use of aryl oxime esters. Unfortunately, the reaction was found rather ineffective with oximes, such as 1 y, delivering the corresponding compound 3 y in poor yield. Then, to demonstrate that our method constitutes a useful approach for the synthesis of complex
在这篇手稿中,建立了一种使用现成的肟酯和1-溴-1,1-二氟丙-2-烯(BDFP)合成烷基取代的偕二氟烯烃的通用光催化方法。这种涉及自由基消除溴的策略提供了获得多种增值氟化分子的途径。温和的反应条件与许多官能团兼容,包括复杂的天然产物或药物分子。实验和理论机理研究表明,该过程的效率取决于亚胺自由基的关键作用,亚胺自由基是在 EnT 光激发和肟酯脱羧后形成的。事实上,亚胺自由基在该反应中要么充当溴自由基清除剂,要么充当 XAT 促进剂。