Catalytic C-O Bond Activation Of Heterocyclic Oxygen Compounds

Transition metal complexes and heteropolyacids have been widelyapplied in catalytic and organic synthesis. As an important class of organiccompounds, diphenylmethane derivatives is usually synthesized by thedehydration of benzyl alcohols or by the dehydrochlorination of benzylchloride with aromatics catalyzed by Lewis acid. On the other handconversion of carbonyl groups to [1,3]dioxolane is a significant kind ofcarbonyl protection reaction. The common methods for the preparation of[1,3]dioxolane is the dehydration of diol with carbonyl groups in the presenceof strong protonic acids. The reported reaction systems mentioned above havesome drawbacks such as hard reaction conditions, environment unfriendly,low productivity. Therefore, the purposes of this work are to develop the newcatalysis systems for activation of C-O bond of heterocyclic oxygencompounds, and their applications on the synthesis of diphenylmethanederivatives and [1,3]dioxolanes.In this dissertation, under air, the dehydration reaction of 1, 3, 5-trioxanewith aromatic compounds catalyzed by ReCl(CO)5, and the ring expansionreaction of epoxides with ketones or aldehydes catalyzed by heteropolyacidshave been investigated in detail. It has been found that 1) ReCl(CO)5 showedgood catalytic activation for the reaction of 1, 3, 5-trioxane with aromaticcompounds affording diarylmethane derivatives in moderate to good yield;2)Heteropolyacids catalyzed the reactions of epoxides with ketone or aldehydesat room temperature producing 1, 3-dioxanes in excellent yield.These results enrich the catalysis systems for activation of C-O bond ofheterocyclic oxygen compounds. In particular, our research work hasdisclosed ReCl(CO)5 is an air-and water-tolerant transition metal catalyst.