Cycloaurated derivatives

Rayama, A., Rinoshita-Nagaoka, J., Rawano, H., Rameda, S. and Mukuriya, M. (1998) Cycloauration of 2-substituted pyridine derivatives. Synthesis, structure and reactivity of srx-membered cycloaurated complexes of 2-anilino-, 2-phenoxy- and 2-(phenylsulfanyl)-pyridine. Journal of the Chemical Society Dalton Transactions, (24), 4095. 

Zhu, Z., Cameron, B.R. and Skerlj, R.T. (2003) Cycloauration of substituted 2-phenoxypyridine derivatives and X-ray crystal structure of gold, dichloro[2-[[5-[(cyclopentylamino)carbonyl]-2-pyridinyl- N]oxy]phenyl- C]-, (SP-4-3)-. Journal of Organometallic Chemistry, 677, 57. 

Fuchita, Y, leda, H Tsunemune, Y, Rinoshita-Nagaoka, J. and Rawano, H. (1998) Synthesis, structure and reactivity of a new six-membered cycloaurated complex of 2-benzoylpyridine [AuCl2(pcp-C, N)] [pep = 2-(2-pyridylcarbonyl) phenyl]. Comparison with the qfcloaurated complex derived from 2-benzylpyridine. Journal of the Chemical Society, Dalton Transactions, (5), 791. 

Most of the substrates that give both types of cycloaurated complexes are limited to pyridine derivatives, although recently a few exceptions have been reported with thiazoles and imidazoles. The reaction of substituted pyridine ligands such as phpy,1 49,1924 2-benzoyl pyridine,1924 2-anili-nopyridine,1925,1926 l-(2-pyridylamino and 2-pyrimidinylamino)naphthalene, 7 2-phenoxypyri-dine,1811 2-(phenylsulfanyl)pyridine,1925 2-(2-thienyl)pyridine, 8 2-(3-thienyl)pyridine,1928 2-(alkylsulfanyl)pyridine,1929 or papavorine1930 at room temperature yields the nonmetallated compounds which, upon heating, are transformed into the metallated complexes [Au(N,C)Cl2], The process with phpy is illustrated in Scheme 21. 

Bipyridine-derived cycloaurated complexes have also been synthesised through the transmetallation route. Conversion of 6-phenyl-2,2 -bipyridine to its organomercury derivative 58, followed by reaction with Na[AuCl4] gave the cycloaurated complex 59 in 38% yield as its [AuC14] salt.39... 

As discussed previously for the formation of five-membered ring cycloaurated complexes (Section II.B), a number of pyridine derivatives also form six-membered cycloaurated products when their AuC13 adducts are heated in the presence of... 

A number of amide derivatives of 114 have also been synthesised. The reactions of the methoxy and hydroxo complexes 162 and 165 with a range of primary and secondary aliphatic and aromatic amines resulted in formation of a number of air-and solution-stable amido derivatives 171-176.74,75 The related monoamido complex containing a cycloaurated benzylpyridine ligand, 177 was also prepared.75 The stability of the toluidine 172 and xylidene 173 complexes in water or a physiological-like buffer solution has been investigated by UV-visible and NMR spectroscopies, and rapid hydrolysis occurred, probably giving the hydroxo complex 165.79... 

Cycloaurated complexes have been used as precursors for the synthesis of a wide range of auracyclic complexes, where the gold atom is also part of an additional metallacycle. Derivatives with C/C-, N/N-, O/O-, C/N- and N/O-donor atoms have all been reported. 

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