Acylation of activated aromatic substrates under mild conditions with (RCO)2O/Me2S/BF3
摘要:
An efficient procedure for acylation and perfluoroacylation of activated aromatic substrates under mild conditions using the system (RCO)(2)O/Me(2)S/BF3 in CH2Cl2 is described. It is believed that dimethylacylsulfonium salts, RCOSMe(2)+ RCO(2)BF(3)-, are the active acylating agents.
Transition‐Metal‐Free C2‐Functionalization of Pyridines through Aryne Three‐Component Coupling
作者:Avishek Guin、Subrata Bhattacharjee、Akkattu T. Biju
DOI:10.1002/chem.202102005
日期:2021.10
C2-functionalization of pyridines through a transition-metal-free protocol by using aryne multicomponent coupling is demonstrated. The reaction allowed a broad-scope synthesis of C2-substituted pyridine derivatives bearing the −CF3 group in good yields with α,α,α-trifluoroacetophenones as the third component. Activated keto esters could also be employed as the third component in this formal 1,2-di(hetero)arylation
展示了通过使用芳炔多组分耦合通过无过渡金属协议直接对吡啶进行 C2 功能化。该反应允许以良好的收率广泛合成带有-CF 3基团的C2-取代的吡啶衍生物,其中α,α,α-三氟苯乙酮作为第三组分。活化的酮酯也可以用作酮的这种正式的 1,2-二(杂)芳基化中的第三组分。在稀释条件下进行反应抑制了竞争性吡啶-芳烃聚合途径。最初生成的亚吡啶中间体对羰基进行亲核攻击,然后进行类似于 Smiles 重排的 S N Ar 过程,得到所需的产物。
N‐Heterocyclic Carbene‐Catalyzed Formal [6+2] Annulation Reaction via Cross‐Conjugated Aza‐Trienolate Intermediates
作者:Kuruva Balanna、Krishnaprasad Madica、Subrata Mukherjee、Arghya Ghosh、Thomas Poisson、Tatiana Besset、Garima Jindal、Akkattu T. Biju
DOI:10.1002/chem.201905177
日期:2020.1.16
The diverse reactivity of N-heterocyclic carbenes (NHCs) in organocatalysis is due to the possibility of different modes of action. Although NHC-bound enolates and dienolates are known, the related NHC-bound cross-conjugated aza-trienolates remain elusive. Herein, we demonstrate the NHC-catalyzed formal [6+2] annulation of nitrogen-containing heterocyclic aldehydes with α,α,α-trifluoroacetophenones
Preparation and behavior of (R)- and (S)-2,2,2-trifluoro-1-(1-pyrenyl)ethanol as chiral solvating agents: study of the diastereomeric association by Job's plots, intermolecular NOE and binding constants
作者:Anna Muñoz、Albert Virgili
DOI:10.1016/s0957-4166(02)00370-1
日期:2002.8
Racemic 2,2,2-trifluoro-1-(1-pyrenyl)ethanol 2, was prepared and the (R)- and (S)-enantiomers obtained by preparative chiral HPLC. The behavior of these compounds as chiral solvating agents is studied with mixtures of several enantiomeric aromatic alcohols and amines. The non-linear distribution of aromatic rings in the pyrene appears to enhance the enantiodiscrimination capacity. (C) 2002 Elsevier Science Ltd. All rights reserved.