and MeI via quaternization of the nitrogen atom of the terminal aminoalkyl groups, and subsequent counteranion exchange by the treatment with AgSbF 6 . Complexes 2a -c and 4a -c have proven to be highly active catalysts for isomerization of allylic alcohols in THF and aqueous media, respectively. Moreover, the water-soluble catalysts 4a -c can be reused after a simple extraction process at the end of the reaction. In particular, 4c presents a remarkable capability to be recycled, being active during 10 successive runs.

Kinetic and spectroscopic analyses were performed to gain information about the mechanism of atom-transfer radical reactions catalyzed by the complexes [RuCl2Cp*(PPh3)] and [RuClCp*(PPh3)2] (Cp*=pentamethylcyclopentadienyl), in the presence and in the absence of the reducing agent magnesium. The reactions of styrene with ethyl trichloroacetate, ethyl dichloroacetate, or dichloroacetonitrile were used as test reactions. The results show that for substrates with high intrinsic reactivity, such as ethyl trichloroacetate, the oxidation state of the catalyst in the resting state is +3, and that the reaction is zero-order with respect to the halogenated compound. Furthermore, the kinetic data suggest that the metal catalyst is not directly involved in the rate-limiting step of the reaction.

The catalytic activity of the arene−ruthenium(II) complexes [RuCl2(η6-p-cymene)(L)] (L = P(OPh)3, P(OMe)3, P(OEt)3, PPh3, P(p-C6H4OMe)3, PMe2Ph, PMe3, PEt3, PCy3) in the isomerization of allylic alcohols into the corresponding saturated ketones has been investigated, the best performances being obtained using [RuCl2(η6-p-cymene){P(OEt)3}]. This compound has proven to be able to catalyze the transformation of poorly reactive substrates of the type R1CHCHCH(OH)R2 and R1CHC(R2)CH(OH)R3 (R1, R2, R3 ≠ H) under very smooth conditions.

A two-step process for the synthesis of trifluoromethyl-substituted cyclopropanes is described. Halothane, an anesthetic agent, is added to olefins in a ruthenium-catalyzed Kharasch reaction. The resulting 1,3-dihalides are converted into cyclopropanes by dehalogenation with magnesium. This procedure represents an alternative to metal-catalyzed cyclopropanations involving trifluoromethyl diazomethane.

Atom‐transfer radical addition (ATRA) reactions of ethyl trichloroacetate, dichloromalononitrile, or diethyl 2,2‐dichloromalonate with olefins followed by dechlorination have provided functionalized cyclopropanes in one step. The RuIII complex [Cp*RuCl2(PPh3)] was used as a catalyst precursor and commercial Mn powder as reducing agent. Reactions with the less activated substrate ethyl dichloroacetate gave ATRA products with high turnover numbers but cyclopropanation was not observed.