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.