Gold complexes pyridines

CsHuN, Ethanamine, A-ethyl-A-methyl-tungsten complex, 26 40, 42 C6HF5, Benzene, pentafluoro-gold complexes, 26 86-90 C H4I2, Benzene, 1,2-diido-iridium complex, 26 125 CJT, Phenyl platinum complex, 26 136 C,H,N, Pyridine osmium complex, 26 291 OHtS, Benzenethiol osmium complex, 26 304 QH7P, Phosphine, phenyl-cobalt-iron complex, 26 353 QH 1-Butyne, 3,3-dimethyl-mercury-molybdenum-ruthenium complex, 26 329-335 C6H 4P, Phosphine, triethyl-platinum complex, 26 126 platinum complexes, 26 135-140 CsHisPO, Triethyl phosphite iron complex, 26 61... 

An interesting transformation involving the indole nucleus was found from propargylic carboxylates to give tetracychc compounds with Au(I) (equation 85). This reaction proceeds by an allene-gold complex in equilibrium with the aUcenyl-gold species, which reacts intramolecularly with the indole to form the product. When the reaction of these substrates is performed with dichloro(pyridine-2-carboxylato)gold(III) or Pt(II) as catalysts, products in equation (86) are obtained instead. This new reactivity can be explained by a formal [3 + 2] cycloaddition of 1,3-dipole... 

Dinuclear gold(I) and gold(II) complexes of pyridine-2-thiolate, 27, 28a and 28b, were studied by cyclic voltammetry at a Pt working electrode in CH2CI234. The dinuclear gold complex, 27, has an irreversible, extended oxidation process at +0.53 V vs SCE. No reduction wave was observed out to —1.8 V. The cyclic voltammograms for the dinuclear gold(II) complexes show irreversible reduction waves at —0.44 V (28a) and —0.43 V (28b). After reduction, the return oxidation scan shows an irreversible oxidation process at +0.55 V, indicative of the presence of 27. 

Many different diazoalkanes lend themselves to these polymerization reactions. Polypentylid-ine, polyhexylidine, polyheptilidine, and polyoctylidine form with a gold complex catalyst, AUCI3-pyridine. ... 

Fig. 7 Pyridine (a) and four different binding possibilities within the pyridine gold complex, namely via N (b), C(3) (c), C(4) (d) and n (e) optimized in structure at DFT level of theory, reproduced from ref. 114. ...

Fig. 8 Molecular orbital diagrams of pyridine and the gold atom as well as the N-binding (AuNPy), C(3)-binding (AuC(3)Py) and it-binding (AuriPy) gold complexes. ...

A unique method to generate the pyridine ring employed a transition metal-mediated 6-endo-dig cyclization of A-propargylamine derivative 120. The reaction proceeds in 5-12 h with yields of 22-74%. Gold (HI) salts are required to catalyze the reaction, but copper salts are sufficient with reactive ketones. A proposed reaction mechanism involves activation of the alkyne by transition metal complexation. This lowers the activation energy for the enamine addition to the alkyne that generates 121. The transition metal also behaves as a Lewis acid and facilitates formation of 120 from 118 and 119. Subsequent aromatization of 121 affords pyridine 122. 

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