Reaction Behaviour of Arylamines with Nitroalkenes in the Presence of Bismuth(III) Triflate: An Easy Access to 2,3-Dialkylquinolines
We report the reaction behaviour between arylamines and nitroalkenes in the presence of bismuth(III) triflate (10 mol %) and diacetoxyiodobenzene (10 mol % ). We obtained 2,3-dialkylquinoline derivatives instead of expected 3-alkylindole derivatives. The present reaction is an alternate approach for the synthesis of 2,3-dialkylquinoline derivatives under milder conditions. Further, we estabilish the mechanistic pathway by theoretical calculation using Gaussian 09 software [B3LYP/6-311+G(d,p)] and it shows that the reaction prefers conventional aza-Michael reaction over Michael addition. Nitroalkenes behave in a different manner than aromatic nitoalkenes. Aza-Michael adduct gives rise to imine by the elimination of water which may tautomerize to correponding enamine. The resulted imine and enamine intermediates react together to afford the desired quinoline derivatives. This protocol provieded consecutive one C-N and two C-C bonds formation, high regioslectivity, broad substrate-scope and good yields.
- This article is part of the themed collection: Synthetic methodology in OBC