ACTIVATION OF CARBON DIOXIDE WITH ALUMINUM PORPHYRIN AND REACTION WITH EPOXIDE. STUDIES ON (TETRAPHENYLPORPHINATO)ALUMINUM ALKOXIDE HAVING A LONG OXYALKYLENE CHAIN AS THE ALKOXIDE GROUP.

Article abstract of DOI:10.1021/ja00343a038

(Tetraphenylporphinato)aluminum alkoxide ((TPP)AIOR) having a long oxyalkylene chain as the alkoxide group was prepared by the polymerization of epoxide with (tetraphenylporphinato)aluminum chloride as catalyst. The reactivity thus trapped with the (porphinato)aluminum alkoxide was found to be activated enough to react with epoxide to afford cyclic carbonate. The spectroscopic investigation of the reaction system, favored by the enhanced solubility of the metalloporphyrin due to the long oxyalkylene chain, indicated that cyclic carbonate was formed by the insertion of carbon dioxide followed by that of epoxide into the aluminum-oxygen bond of (TPP)AlOR to give the aluminum alkoxide (TPP)Al-O-CHR-CH//2-O-CO-OR and subsequent intramolecular attack of this aluminum alkoxide toward the adjacent linear carbonate linkage, regenerating the starting alkoxide, (TPP)AlOR. This work is pertinent to biochemical photosynthesis.