18109-36-9Relevant academic research and scientific papers
Visible light-promoted copper catalyzed regioselective acetamidation of terminal alkynes by arylamines
Pampana, V. Kishore Kumar,Sagadevan, Arunachalam,Ragupathi, Ayyakkannu,Hwang, Kuo Chu
supporting information, p. 1164 - 1170 (2020/03/11)
Herein, we describe a copper photoredox catalyzed synthesis of acetamide via regioselective C-N coupling of arylamines with terminal alkynes using molecular oxygen (O2) as an oxidant at room temperature under visible light irradiation (47 examples). Unique simultaneous formation of both amide and ester functionalities occurs via intramolecular cyclization in a single-step reaction in the case of anthranilic acids using inexpensive copper as a catalyst and eco-friendly O2 as an oxidant and reagent. Different substrates undergo different reaction pathways to generate similar acetamide products, as evidenced by 18O2 labelling experiments. The current protocol was also applied for the rapid, few step preparation of biologically active inhibitors (BACE-1 and PDE4). This process can be readily scaled up to a gram scale, and calculations of green metrics suggest the economic feasibility and eco-friendly nature of the current photoredox approach.
Hydrative syntheses of amides from alkynes catalyzed by an Au(I) complex containing pyridyl-functionalized NHC ligand
Singh, Kuldeep,Pal, Nilay Kumar,Guha, Chirajyoti,Bera, Jitendra K.
, p. 1 - 8 (2019/02/25)
An Au(I)-NHC complex [L1AuBr] (1) with appended pyridyl group on the ligand scaffold is synthesized and its catalytic efficacy for the direct synthesis of the amide from alkyne and sodium azide in acidic water is evaluated. Catalyst 1 readily converts a wide range of internal and terminal alkynes to the corresponding amides with low catalyst loading in TFA/DCE (2 mL, 1:1 v/v) at room temperature in short reaction time (2 h) and without the use of Ag(I) additive. A related catalyst that is devoid of the pyridyl fragment displays significantly lower activity illustrating the role of the promoter ligand for water activation. Mechanistic studies reveal an initial alkyne hydration to ketone followed by the Schmidt reaction to afford the amide.
