Amidate-bridged Pt III dinuclear complexes [Pt 2 (NH 3 ) 4 (Am) 2 (H 2 O) 2 ] 4+ (Am ) amidate ligand) catalyze oxidation of olefins in acidic aqueous solution. Linear olefins are oxidized to ketones, whereas cyclic olefins are oxidized to epoxides. GC-MS analysis of the oxidation products obtained from the reaction in H 2 18 O showed that the oxygen atoms in the products are exclusively from water, suggesting that the reaction mechanism is basically similar to that of the Wacker reaction. In accordance with this mechanism, pivalamidate-bridged Pt III complex [Pt III 2 (NH 3 ) 4 ((CH 3 ) 3 CCONH) 2 (H 2 O) 2 ] 4+ has been found to react with olefins to give alkyl complexes. Reactions with 4-penten-1-ol and ethylene glycol vinyl ether in acidic aqueous solution gave [Pt III 2 (NH 3 ) 4 ((CH 3 ) 3 CCONH) 2 (CH 2 CH(CH 2 ) 3 O)](NO 3 ) 3 ‚H 2 O (7) and [Pt III 2 (NH 3 ) 4 ((CH 3 ) 3 CCONH) 2 (CH 2 CHO)]-(NO 3 ) 3 ‚H 2 O (9), respectively. The two compounds have been structurally confirmed by X-ray diffraction analysis and 1 H, 13 C, and 195 Pt NMR spectroscopy. The 1 H NMR of 9 shows that both π-and σ-complexes exist in equilibrium in D 2 O, although the X-ray structure is close to the σ-complex. High electrophilicity of the R-carbon atoms of the compounds has been shown in the reactions with OH -. The above reactions with olefins can be a general route to prepare dimeric Pt III -alkyl complexes.

The first olefin epoxidation by water oxygen is reported. The reaction is catalyzed by platinum blue complexes and is the first example that water oxygen atom is introduced into epoxides in catalytic or stoichiometric reaction.

ABSTRACT:The photolysis of dimethyl (2R*,4R*)-2-bromo-2,4-dimethyl-4-(2,2,2-trichloroethyl)glutarate was examined and reaction paths for ten products are proposed. A homolytic cleavage of the carbon-bromine bond of the substrate occurred first forming a radical intermediate and subsequent reactions yielded the products via decomposition of the intermediate and recombination of secondly formed radical species. Ionic lactonization of the substrate and diastereoisomerization proceeded simultaneously.KEY WORDS Photolysis / Telomer / Methyl Methacrylate Dimer Homolytic Cleavage / Carbon-Bromine Bond / Recombination Diastereoisomerization / Lactonization / The photochemistry of organic halides is characterized by cleavage of the carbon-halogen bond. 1 · 2 In recent studies on the solution photoreaction of aliphatic halides, 3 -5 workers have concentrated their attention on understanding whether the products are formed from a radical species or from an ionic one.We previously reported the photolysis of methyl 2-bromo-4,4,4-trichloro-2-methylbutyrate (1) 6 obtained from the telomerization of methyl methacrylate (MMA) using bromotrichloromethane (BTCM) as a telogen. 7 In the preceding paper,8 we described the effects of copper powder on the photolysis of 1. The results indicated that the conversion of the substrate and amount of products via a homolytic cleavage of the carbon-bromine bond increased with the amount of copper powder added. Since there have been a few studies on the photochemistry of aliphatic * To whom all correspondence should be addressed.halides containing different halogen atoms, 9 • 10 we had interest in the photochemistry of telomers such as 1.meso-and di-Dimers of MMA with a headto-head linkage, formed by recombination of the tertiary carbon radicals produced by a homolytic cleavage of the carbon-bromine bond, are interesting. Rae et al. reported the synthesis and characterization of the mesoand di-isomers of tetramethyl 2,4,5,7-tetramethyloctane-2,4,5, 7-tetracarboxylate and thermal degradation of its meso-isomer as a model to study the effects of head-to-head linkage in thermal degradation of poly-(MMA). 11,12

An SÀ N variant of the NÀ N-based Fischer indole synthesis has been developed. Treatment of sulfonanilides and ketene dithioacetal monoxides with a powerful acid anhydride provides N-sulfonyl-2-methylsulfanylindoles. The initial interrupted Pummerer reaction would yield the key SÀ N-tethered precursor in situ that then undergoes [3,3] sigmatropic rearrangement, after which the endgame to the indole ring follows the Fischer manner.