Amidation metalloporphyrins

The above-described structures are the main representatives of the family of nitrogen ligands, which cover a wide spectrum of activity and efficiency for catalytic C - C bond formations. To a lesser extent, amines or imines, associated with copper salts, and metalloporphyrins led to good catalysts for cyclo-propanation. Interestingly, sulfinylimine ligands, with the chirality provided solely by the sulfoxide moieties, have been also used as copper-chelates for the asymmetric Diels-Alder reaction. Amide derivatives (or pyridylamides) also proved their efficiency for the Tsuji-Trost reaction. 

Complexes of rhenium(bipyridine)(tricarbonyl)(picoline) units linked covalently to magnesium tetraphenylporphyrins via an amide bond between the bipyridine and one phenyl substituent of the porphyrin 19 exhibited no signs of electronic interaction between the Re(CO)3(bpy) nnits and the metalloporphyrin units in their gronnd states. However, emission spectroscopy revealed a solvent-dependent quenching of porphyrin emission upon irradiation into the long-wavelength absorption bands localized on the porphyrin. 

Cytochrome P-450 can perform both intramolecular and intermolecular nitrene insertions with 106 in water solution [181]. However, the intermediate metallo-nitrene (108) also hydrolyzed to some extent so the enzyme performed a hydroxylation as well as an amidation. Although we have also performed an intermolecular amidation of a steroid, using such a metalloporphyrin reaction with 106 to form 112 [182], we have not yet extended it to the kinds of directed functionalizations described above with either benzophenones or chlorinations. 

Receptor 33 also incorporates a secondary Lewis acid anion binding site. This molecule is the zinc metallated ansdogue of 17 with the cobal-tocenium reporter groups replaced with ferrocenes [27]. The freebase precursor to 33 in dichloromethane solution shows no significant anion induced shifts in the H NMR signals of the amide protons, whereas the metalloporphyrin binds bromide (JC = 6200M ), nitrate (K = 2300M i)... 

IV-Tosyliminoiodanes, ArINTs, have found synthetic application as useful nitrene precursors in transition metal catalyzed amidation of saturated C—H bonds in various organic substrates. Breslow and coworkers have developed the regioselective amidation of steroidal derivatives catalyzed by metalloporphyrins [690,691]. Specifically, the aromatic steroid equilenin acetate 657 undergoes regioselective and stereoselective amidation catalyzed by a manganese porphyrin using PhINTs as the nitrene donor (Scheme 3.261) [690],... 

The coordination catalysts for these reactions are diverse. They can be compounds of alkaline earth metals, like calcium amide, or calcium amide-alkoxide. They can also be Ziegler-Natta-type catalysts. These can be alkoxides of aluminum, magnesium, or zinc combined with ferric chloride. Others are reaction products of dialkylzinc with water or alcohol. They can also be bimetallic //-oxoalkoxides, such as [(RO)2A102]Zn. Other catalysts are aluminum or zinc metalloporphyrin derivatives (see Fig. 4.1). 

Metalloporphyrins and metallocorroles have been shown to acts as alkene aziridina-tion catalysts, and the extent of macrocycle halogenation has been shown to correlate with catalyst performance. Mn(III) complexes of 5,10,15-Tris(pentafluorophenyl) corrole are active in aziridination catalysis [101, 102] electron-withdrawing substituents on the corrole are required to facilitate amide transfer to the alkene. Fluorination of corroles also leads to stable metal imide intermediates during aziridination reactions. 

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