Aluminum porphyrins synthesis

Kuroki, M. Nashimoto, S. Aida, T. Inoue, S. Sequential addition-ring-opening living polymerizations by aluminum porphyrin. Synthesis of alkyl methacrylate-epoxide and -lactone block copolymers of controlled molecular weight. Macromo/ec Ze 1988, 21, 3114—3115. 

The CO2 activation reactions seen for aluminum porphyrins are also observed for In(Por)Me (Por = OEP, TPP), which will insert CO2 in the presence of pyridine and under irradiation by visible light to give the acetato complex In(Por)OC(0)Me. The indium acetato product has been characterized by X-ray crystallography, whereas in the aluminum complex it was observed only by spectroscopy. An alternative synthesis of the acetato complex is by treatment of ln(Por)Cl by alumina and water, followed by acetic acid. For the indium and... 

In the present section we describe the living anionic polymerization of meth-acrylonitrile by two initiating systems such as the aluminum porphyrin-Lewis acid system and the aluminum porphyrin-Lewis base system which enables the synthesis of poly(methyl methacrylate-h-methacrylonitrile)s of controlled molecular weights. 

By using the aluminum porphyrin-Lewis acid system, we attempted the synthesis of a narrow MWD block copolymer from oxetane and methyl methacrylate (MMA). Methacrylic monomers can be polymerized radically and anioni-cally but not cationically, so a block copolymer of oxetane and methyl methacrylate has never been synthesized. As already reported, methacrylic monomers undergo accelerated living anionic polymerization with the (TPP)AlMe (1, X= Me)-3e system via a (porphinato)aluminum enolate as the growing species. 

Aluminum May activate succinic dehydrogenase and 6-aminolevuimate de-hydrase. The latter is involved in porphyrin synthesis/... 

Another carbon dioxide insertion reaction is observed with Al (TPP)(OMe) This compound readily and reversibly traps carbon dioxide at room temperature in the presence of 1-methylimidazole. The trapped carbon dioxide is sufficiently activated to react with an epoxide at room temperature, thus producing the corresponding alkylcarbonate. As illustrated in Scheme 11, the cyclic carbonate is considered to be formed - at least partly - by nucleophilic attack on a linear intermediate. Thus the alkoxide aluminum porphyrin-methylimidazole system would be a good catalyst for synthesis of alkylene carbonates from carbon dioxide and epoxides under mild conditions. 

Sugimoto, H., Saika, M., Hosokawa, Y., Aida, T., and Inoue, S., 1996, Accelerated Living Polymerization of Methacrylonitrile with Aluminum Porphyrin Initiators ity Activation of Monomer or Growing Species. Controlled Synthesis and Properties of Poly(medtyl methactylate-b-methaciylonitrile)s, Macromolecules, 29 3359... 

Lewis acid-assisted high-speed living anionic polymerization can be applied not only to the accelerated synthesis of naiTOw MWD poly(methacrylic esters) but also to the synthesis of polyethers from epoxides (11) and polyesters from lactones (14 and 15) with aluminum porphyrins as initiators. Furthermore, ring-opening polymerization of episulfides (18) with zinc AT-substituted porphyrins (5) can also be accelerated by Lewis acids. 

Adachi, T. Sugimoto, H. Aida, T. Inoue, S. Controlled synthesis of high molecular weight poly(methyl methacrylate) based on Lewis acid-assisted high-speed living polymerization initiated with aluminum porphyrin. Macromolecules 1992, 25, 2280-2281. 

Sugimoto, H. Saika, M. Hosokawa, Y. Aida, T. Inoue, S. Accelerated living polymerization of methacrylonitrile with aluminum porphyrin initiators by activation of monomer or growing species. Controlled synthesis and properties of poly(methyl methacrylate-i>-methacrylonitrile)s. Macromolecules 1996, 29, 3359-3369. 

The discovery by Inoue (20) that epoxides and carbon dioxide could be copolymerized in the presence of a diethylzinc water catalysts offers an additional route to aliphatic polycarbonates. The catalyst types which are effective for this polymerization were expanded upon in later work, demonstrating that zincipyrogallol (21) and aluminum-porphyrin (22) catalyst systems afforded the desired linear polycarbonates. The synthesis has been applied to fimctional epoxides with pendent hydroxy (23) and o-nitrobenz)d ether groups (24), the later being investigated as a new photoresist scheme. 

The synthesis of the novel tetrafuran-containing macrocycle 4.178 was reported in 1992. This macrocycle was prepared by the aldol-type condensation between diketone 4.176 and dialdehyde 4.177 in 20% yield (Scheme 4.5.2). Subjecting this macrocycle to reductive deoxygenation using lithium aluminum hydride and aluminum trichloride afforded the tetraoxaporphyrinogens-(3.0.3.0) 4.179 and 4.180 in combined 35% yield (Scheme 4.5.3). These two isomeric products, formed in 55% and 45% relative abundance, respectively, could not be readily separated. Instead, they were treated together (i.e., as a mixture) with p-chloranil to afford the conjugated tetraoxa[22]porphyrin-(3.0.3.0) species 4.181 in 15% yield (Scheme 4.5.4). 

Guilard, R., Lopez, M. A., Tabard, A., Richard, P., Lecomte, C., Brandes, S., Hutchison, J. E., Collman, J. P. (1992). Synthesis and characterization of novel cobalt aluminum cofacial porphyrins. First crystal and molecular structure of a heterovimetallic biphenylene pillared cofacial diporphyrin, /. Am. Chem. Soc., 114 9877. 

Braune and Okuda have shown the possibility to substitute porphyrin initiators by simpler systems based on the association of ammonium salts with a bulky aluminum bis(phenolate) electrophile. According to their study, the ring-opening polymerization of PO cannot occur at simple Lewis add centers, but that nucleophilic ate complexes must be present at the same time. However, so far, only the synthesis of PPO oligomers with MWs less than 5000 has been reported for this system. The important contribution of Braune and Okuda is that they confirmed the Vandenberg binudear mechanism earlier proposed for epoxide polymerization (see Figure 12). °- ... 

---