Water-soluble (salicyladimine)2Cu complex as an efficient and renewable catalyst for Michael addition of indoles to nitroolefins in water

ABSTRACT An efficient and environmentally friendly protocol has been demonstrated for water-soluble (salicyladimine)2Cu complex-catalyzed Michael addition of indoles to nitroolefins in water at 30 °C. A variety of substituted indoles and β-nitrostyrenes could be worked well to provide the title products in 81–97% yields. Moreover, the catalyst can be reused directly at least for four times without significantly decreasing activity. GRAPHICAL ABSTRACT

[1]  A. Kost,et al.  Chemistry of indoles , 1975 .

[2]  B. Roth,et al.  2-Substituted tryptamines: agents with selectivity for 5-HT(6) serotonin receptors. , 2000, Journal of medicinal chemistry.

[3]  Some Selected Examples , 2004 .

[4]  N. Iranpoor,et al.  The facile and efficient Michael addition of indoles and pyrrole to alpha,beta-unsaturated electron-deficient compounds catalyzed by aluminium dodecyl sulfate trihydrate [Al(DS)3].3H2O in water. , 2005, Chemical communications.

[5]  Masakatsu Shibasaki,et al.  A bench-stable homodinuclear Ni2-Schiff base complex for catalytic asymmetric synthesis of alpha-tetrasubstituted anti-alpha,beta-diamino acid surrogates. , 2008, Journal of the American Chemical Society.

[6]  Veerababurao Kavala,et al.  Catalyst-free aqueous-mediated conjugative addition of indoles to β-nitrostyrenes , 2008 .

[7]  Yu Yuan,et al.  Efficient iron-catalyzed Michael addition of indole to nitroolefins under solvent-free conditions , 2013, Research on Chemical Intermediates.

[8]  D. Enders,et al.  Enantioselective synthesis of tetrahydrocarbazoles through a Michael addition/Ciamician-Plancher rearrangement sequence: asymmetric synthesis of a potent constrained analogue of MS-245. , 2012, Chemistry.

[9]  Roya Jahanshahi,et al.  Nano n-propylsulfonated γ-Fe2O3 (NPS-γ-Fe2O3) as a magnetically recyclable heterogeneous catalyst for the efficient synthesis of 2-indolyl-1-nitroalkanes and bis(indolyl)methanes , 2013 .

[10]  Jianwei Xie,et al.  A simple and efficient 2N2O–Cu(II) complex as a catalyst for N‐arylation of imidazoles in water , 2015 .

[11]  Ping Liu,et al.  Highly selective copper‐catalyzed oxidation of benzyl alcohols to aromatic aldehydes in water at room temperature , 2016 .