title: Crown ether complex cation ionic liquids: preparation and applications in organic reactions.
abstract: A series of crown ether complex cation ionic liquids (CECILs) were designed, synthesised and characterised by NMR spectroscopy, HRMS, thermogravimetric differential thermal analysis (TG-DTA) and elemental analysis. Their applications in various organic reactions were investigated: [15-C-5Na][OH], [15-C-5Na][OAc], [18-C-6K][OH] and [18-C-6K][OAc] (15-C-5=[15]crown-5; 18-C-6=[18]crown-6) efficiently catalysed the Michael addition of alkenes and relevant nucleophiles; [18-C-6K][OH] and [15-C-5Na][OH] effectively catalysed the Henry reaction of nitromethane and aromatic aldehydes; [18-C-6K][OH] has excellent catalytic efficiency for Knoevenagel condensation of aromatic aldehydes and malononitrile; PdCl(2) /[18-C-6K](3)[PO(4)]/K(2)CO(3) efficaciously catalysed the Heck reaction of olefins and aromatic halides; [18-C-6K][BrO(3)] can be used as both oxidant and solvent in the oxidation reaction of aromatic alcohols. The CECIL catalysts [15-C-5Na][OH] (Michael addition) and [18-C-6K][OH] (Henry reaction) can be recycled and reused several times without obvious loss of activity and their recovery is very simple.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, PR China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Song
authors.forename: Huanwang
authors.initials: H
authors.lastname: Jing
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Bai