Hydroesterification and hydroformylation of 1-hexene catalyzed by rhodium complexes immobilized on poly(4-vinylpyridine)

This work describes the catalytic hydroesterification and hydroformylation of 1-hexene by [Rh(cod)(amine)2](PF6) complexes (cod = 1,5-cyclooctadiene; amine = pyridine, 2-picoline, 3-picoline, 4-picoline, 3,5-lutidine or 2,6-lutidine) immobilized on poly(4-vinylpyridine) in contact with methanol under carbon monoxide atmosphere. In the presence of these immobilized complexes, 1-hexene, CO and methanol give methyl-heptanoate and 1,1-dimethoxy-heptane as the main reaction products and minor amounts of heptanal. The acetal by-product comes from the nucleophilic addition reaction of the methanol with the formed heptanal. Other products, such as H2 and CO2 coming from the catalysis of the water-gas shift reaction are observed. The reaction products distribution depends on the nature of the coordinated amine to the rhodium center and the reaction parameters.