Synthesis of oxocyclohexenecarboxylic acids and podands derived therefrom under heterogeneous catalysis

摘要

Nanosized Al, Mg, and Ti-Si oxides, as well as barium hydroxide, have been tested as heterogeneous catalysts in the Robinson reaction with 2-ethoxy-substituted chalcone and podands based thereon. Barium hydroxide catalyzes the first step of the Robinson reaction, Michael addition, while its activity in the second step involving intramolecular cyclization and dehydration is lower. Nanosized oxides effectively catalyze the second step of the Robinson reaction and hamper elimination of the carboxy group. Procedures have been developed for the synthesis of oxocyclohexenecarboxylic acid derivatives and symmetric and asymmetric podands based thereon.