François Simal

HIGHLY EFFICIENT RUTHENIUM-BASED CATALYTIC SYSTEMS FOR THE CONTROLLED FREE-RADICAL POLYMERIZATION OF VINYL MONOMERS

A new set of ruthenium complexes such as 1 and 2 (the Grubbs ruthenium-carbene complex) has been shown to mediate the controlled atom-transfer radical polymerization (ATRP) of vinyl monomers with exceptional efficiency. Furthermore, there is a striking parallelism between the catalytic activity of these compounds in olefin metathesis and in ATRP.

Synthesis and evaluation of new RuCl2(p-cymene)(ER2R′) and (η1:η6-phosphinoarene)RuCl2 complexes as ring-opening metathesis polymerization catalysts

Abstract New RuCl 2 ( p -cymene)(ER 2 R′) complexes (E=P, As, Sb; R, R′=H, alkyl, arylalkyl) have been synthesized and used as catalyst precursors for the ring-opening metathesis polymerization (ROMP) of cyclooctene, cyclopentene, and norbornene. When ER 2 R′ was a phosphinoarene, the p -cymene ligand could be displaced upon heating and tethered (η 1 :η 6 -phosphinoarene)RuCl 2 complexes were obtained. Simple thermogravimetric analysis (TGA) of the complexes provided clear-cut indication on their potential catalytic activity in ROMP.

Radical reactions catalysed by ruthenium(II) complexes with anionic carborane phosphine ligands: Kharasch addition to olefins and controlled polymerisation

Abstract Ruthenium-carborane complexes 1 – 3 mediated the Kharasch addition of carbon tetrachloride across olefins with high yields which markedly depended on the catalyst and the substrate used. In addition, the atom transfer radical polymerisation of methyl methacrylate could be carried out in a highly controlled way.

Highly efficient Kharasch addition catalysed by RuCl(Cp*)(PPh3)2

Air-stable and readily available RuCl(Cp*)(PPh3)2 is so far the best ruthenium-based catalyst precursor for promoting the addition of CCl4 and CHCl3 across olefins at a temperature as low as 40°C.

New, Highly Efficient Catalyst Precursors for Kharasch Additions − [RuCl(Cp*)(PPh3)2] and [RuCl(Ind)(PPh3)2]

[RuCl(Cp*)(PPh3)2] and [RuCl(Ind)(PPh3)2] are excellent catalyst precursors for promoting the Kharasch addition of CCl4 and CHCl3 across olefins under mild reaction conditions (at temperatures as low as 40 °C with CCl4). The effect of the substituents on the cyclopentadienyl ring has been investigated. In terms of efficiency and activity, [RuCl(Cp*)(PPh3)2] and [RuCl(Ind)(PPh3)2] surpass the best ruthenium systems reported so far. A two-step mechanism, in which the extrusion of a phosphane ligand occurs prior to the activation of the halogenated compound by the unsaturated ruthenium center, is suggested.

SYNTHESIS AND EVALUATION OF RUTHENIUM CATALYSTS CONTAINING DIAMINE-BASED LIGANDS IN OLEFIN CYCLOPROPANATION

Abstract Ruthenium complexes with N -( p -toluenesulfonyl)-diamine ligands were found to be efficient in the catalytic cyclopropanation reaction of olefins with alkyl diazoacetate.

OLEFIN CYCLOPROPANATION CATALYSED BY NOVEL RUTHENIUM-ARENE COMPLEXES CONTAINING PHOSPHINES WITH PENDENT ARENES

Abstract Ruthenium-arene complexes containing phosphines with pendent aryl groups [RuCl 2 ( η 6 - p -cymene)(PCy 2 (CH 2 ) 3 Ar)], Ar  C 6 H 5 and 3,5-(CH 3 ) 2 C 6 H 3 ( 1 and 3 ), and the resulting chelating complexes [RuCl 2 (PCy 2 (CH 2 ) 3 -η 6 -Ar)] ( 2 and 4 ) mediate the cyclopropanation of olefins with ethyl diazoacetate. Comparison of the reactivity patterns of these complexes indicates that p -cymene disengagement is likely the key step in the reactions catalysed by non-chelating complexes 1 and 3 .

Half-sandwich ruthenium complexes for the controlled radical polymerisation of vinyl monomers

Abstract Ruthenium complexes of the type [RuX(Cp # )(PPh 3 ) 2 ] (X=Cl and H; Cp # =Cp, Cp*, indenyl, and carboranyl) catalyse the radical polymerisation of styrene and n -butyl acrylate, and both the catalyst activity and the degree of control of the polymerisation strongly depend on the Cp # ligand and the monomer.

Cp*Ru(II) and Cp*Ru(IV)-catalyzed reactions of CHX with vinyl C–H bonds: competition between double bond homologation and olefin cyclopropanation by alkyl diazoacetate

When diazoesters are used as carbene precursors, new Ru(II) and Ru(IV) complexes bearing various substitutents tethered ligands mediate the formal carbene insertion into C–H vinyl bonds of (substituted) styrenes to yield mostly E- and Z-styrylacetic esters (e.g. 4-phenylbut-3-enoates with styrene). This rarely observed reaction competes with the cyclopropanation of the double bond. The influence of steric and electronic factors on the two competitive reactions is reported. The observation that the most efficient C–H insertion catalysts also promote the ROMP of norbornene lend support to the formation of ruthenacyclobutanes as reaction intermediates.

Cyclopropanation reactions catalysed by rhodium(I) complexes with new anionic carborane phosphine ligands

Abstract The first set of rhodium(I) complexes 1–3 has been shown to be active for the cyclopropanation of olefins with diazoacetates.