An amphiphilic resin-dispersion of nanoparticles of platinum (ARP-Pt): a highly active and recyclable catalyst for the aerobic oxidation of a variety of alcohols in water.

An amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-dispersion of nanoparticles of platinum (ARP-Pt, 4) was developed with a view towards use in catalysis in an aqueous environment under heterogeneous conditions. ARP-Pt 4 was prepared by the reduction of PS-PEG-NH(2)-PtCl(2)(C(2)H(4)) 3, which was generated by mixing PS-PEG-NH(2) 1 and Zeise's salt 2 (K[PtCl(3)(CH(2)CH(2))]), with benzyl alcohol in water (80 degrees C, 12 h). Benzyl alcohol was an essential reducing agent for the preparation of Pt nanoparticles with a narrow size distribution (phi = 5.9+/-0.75 nm) throughout the PS-PEG resin, whereas the reduction of 3 with NaBH(4) gave Pt nanoparticles with broad size distribution (phi = 2-150 nm). ARP-Pt 4 was found to catalyze the aerobic oxidation of a wide variety of alcohols, including non-activated aliphatic and alicyclic alcohols, in water with atmospheric oxygen or air under heterogeneous conditions, and was reused without loss of its catalytic activity, to achieve a highly environmentally-friendly reaction.

Asymmetric Suzuki-Miyaura coupling in water with a chiral palladium catalyst supported on an amphiphilic resin.

You oughta use water: Broad functional-group (FG) tolerance was observed for the title coupling of aryl halides (X = Cl, Br, I) and aryl boronic acids to give biaryl compounds with up to 94% ee. The chiral imidazoindole phosphine-palladium catalyst supported on an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin could be recycled readily.

Ruthenium(II)-catalyzed selective intramolecular [2 + 2 + 2] alkyne cyclotrimerizations.

In the presence of a catalytic amount of Cp*RuCl(cod), 1,6-diynes chemoselectively reacted with monoalkynes at ambient temperature to afford the desired bicyclic benzene derivatives in good yields. A wide variety of diynes and monoynes containing functional groups such as ester, ketone, nitrile, amine, alcohol, sulfide, etc. can be used for the present ruthenium catalysis. The most significant advantage of this protocol is that the cycloaddition of unsymmetrical 1,6-diynes with one internal alkyne moiety regioselectively gave rise to meta-substituted products with excellent regioselectivity. Completely intramolecular alkyne cyclotrimerization was also accomplished using triyne substrates to obtain tricyclic aromatic compounds fused with 5-7-membered rings. A ruthenabicycle complex relevant to these cyclotrimerizations was synthesized from Cp*RuCl(cod) and a 1,6-diyne possessing phenyl terminal groups, and its structure was unambiguously determined by X-ray analysis. The intermediary of such a ruthenacycle intermediate was further confirmed by its reaction with acetylene, giving rise to the expected cycloadduct. The density functional study on the cyclotrimerization mechanism elucidated that the cyclotrimerization proceeds via oxidative cyclization, producing a ruthenacycle intermediate and subsequent alkyne insertion initiated by the formal [2 + 2] cycloaddition of the resultant ruthenacycle with an alkyne.

Ru(II)-catalyzed [2 + 2 + 2] cycloaddition of 1,2-bis(propiolyl)benzenes with monoalkynes leading to substituted anthraquinones.

[2 + 2 + 2] cycloadditions of 1,2-bis(propiolyl)benzenes with monoalkynes were effectively catalysed by Cp*RuCl(cod) under mild conditions to give substituted anthraquinones in moderate to high yields.