Mannich reactions scandium triflate

Scandium triflate-catalyzed aldol reactions of silyl enol ethers with aldehyde were successfully carried out in micellar systems and encapsulating systems. While the reactions proceeded sluggishly in water alone, strong enhancement of the reactivity was observed in the presence of a small amount of a surfactant. The effect of surfactant was attributed to the stabiMzation of enol silyl ether by it. Versatile carbon-carbon bondforming reactions proceeded in water without using any organic solvents. Cross-linked Sc-containing dendrimers were also found to be effective and the catalyst can be readily recycled without any appreciable loss of catalytic activity.Aldol reaction of 1-phenyl-l-(trimethylsilyloxy) ethylene and benzaldehyde was also conducted in a gel medium of fluoroalkyl end-capped 2-acrylamido-2-methylpropanesulfonic acid polymer. A nanostmctured, polymer-supported Sc(III) catalyst (NP-Sc) functions in water at ambient temperature and can be efficiently recycled. It also affords stereoselectivities different from isotropic solution and solid-state scandium catalysts in Mukaiyama aldol and Mannich-type reactions. 

Polynitroalkanes undergo Henry and Mannich reactions in ionic liquids. TMS-methylenenitronate (75) reacts with aliphatic and aromatic aldehydes to give Henry reaction products, with scandium(III) triflate as catalyst. ... 

Kobayashi and coworkers showed that Lewis add surfactant-combined catalysts such as scandium tris(dodecyl sulfate), Sc(03SCi2H25)3, or copper bis(dodecyl sulfate), Cu(03SCi2H25)2, were efficient catalysts for the three-component Mannich-type reaction, with 73-95% yield being obtained in neat water.Neutral salts such as sodium triflate and sodium iodide catalyzed the condensation reaction in water between preformed imines and silicon enolates, or the three-component Mannich-type reaction using aromatic amines, with 49-93% yields and 0-80% diastereoselectivities. Mechanistic studies indicated that both sodium triflate and the Mannich adduct itself cooperatively promote the reaction. 

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