[Development of polymer-supported pi-acid catalysts].
We reported that dicyanoketene acetals (DCKA), in which gem-dicyano groups of tetracyanoethylene (TCNE) are displaced with alkoxyl groups, function as pi-acid catalysts, and that a polymer (poly-DCKA-1) derived by copolymerization of a monomer, in which the alkoxyl group at the omega-position is modified with a styrene moiety, with ethyleneglycol dimethacrylate also shows high level of activities as a pi-acid. In this research, the effects of dicyanoketene ethylene acetal (DCKEA), polymers previously developed (poly-DCKA-1 and 2), new monomers, in which the alkoxyl group at the omega-position is modified with an ethereal moiety, and the corresponding polymers (poly-DCKA-3 and 4) were investigated on catalytic activities. Among the catalysts, the polymer (poly-DCKA-1) had the most efficient activity in monothioacetalization, cyanation, and Mukaiyama aldol reaction of acetals, two-component and three-component Mannich-type reaction, hydrolysis of acetals and silyl ethers, and two-component and three-component inverse electron demand Aza-Diels-Alder reaction. Remarkably, the polymer catalyst works more efficiently in water than in organic solvents and is recyclable.
Masaki
Yukio
Y
Gifu Pharmaceutical University, Japan. masakiy@ccmfs.meijo-u.ac.jp
D000080:Acetals / Q000737:chemistry*; D000143:Acids / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic; D055601:Organic Chemistry Phenomena; D011108:Polymers / Q000737:chemistry; D014867:Water
D000080:Acetals; D000143:Acids; D011108:Polymers; D014867:Water; D002244:Carbon