Synthesis of trifluoromethyl-substituted cyclopropanes via sequential Kharasch-dehalogenation reactions.

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.

Chiral phosphonite, phosphite and phosphoramidite eta6-arene-ruthenium(II) complexes: application to the kinetic resolution of allylic alcohols.

The synthesis and characterization of chiral arene-ruthenium complexes [RuCl(2)(eta(6)-arene){(R)-PR(binaphthoxy)}] (arene = benzene (1), p-cymene (2), mesitylene (3); R = Ph (a), OPh (b), piperidyl (c)) are described. Derivatives 1-3 have been employed to promote the kinetic resolution of allylic alcohols through a redox-isomerization process. As a general trend, the best selectivities are attained with the more sterically hindered catalysts i.e. those containing p-cymene or mesitylene ligands.

Atom-transfer radical addition reactions catalyzed by RuCp* complexes: a mechanistic study.

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.