Novel Polymer Effect in Cleavage Reactions of Acetals and Silyl Ethers in Aqueous Media Catalyzed by a Polymer-Supported Dicyanoketene Acetal
31 December 2001 (online)
Deprotecting reactions of acetals including acetonides, ethylene acetals, and THP ethers of alcohols, an aldehyde, and ketones, and silyl ethers of primary and secondary alcohols were investigated using dicyanoketene acetals (DCKA) and a polymer-supported DCKA as a π-acid promoter in aqueous acetonitrile and a single aqueous medium. In all reactions catalytic activity of the polymer-supported DCKA was found to be much higher than that of the molecular DCKAs and an excellent polymer effect was observed. Particularly in the deacetalization reactions in water, difference of catalytic efficiency between the polymer-supported DCKA and the molecular DCKAs was remarkable.
polymeric dicyanoketene acetal - polymer effect - catalysis in aqueous media - deacetalization - desilylation