Bernard Demerseman

Ruthenium(IV) Complexes Featuring P,O‐Chelating Ligands: Regioselective Substitution Directly from Allylic Alcohols

Branching out: A new ruthenium(IV) complex (1), containing a P,O-chelating ligand, is an efficient precatalyst for regioselective allylations starting from various allylic alcohol derivatives.

Ruthenium-Catalyzed Synthesis of Allylic Alcohols : Boronic Acid as a Hydroxide Source

Secondary allylic alcohols were synthesized from linear allylic halides or carbonates using a catalytic amount of a ruthenium complex in the presence of boronic acid. The effects of solvent, base, ruthenium precursor, and boronic acid were fully explored, and the scope of the reaction was extended to various substrates. We also describe a preliminary investigation towards an enantioselective process.

Ruthenium catalysts for selective nucleophilic allylic substitution

Recent developments in the chemistry of η3-allylruthenium(IV) complexes are due to their straightforward synthesis resulting from oxidative addition of allylic substrates to a ruthenium(II) center. Subsequent reaction with a nucleophile is the basis of their involvement in the catalytic allylic substitution reaction. We focus here on ruthenium-catalyzed substitution of allylic substrates by C-, N-, and O-nucleophiles and show that selected ligands make regio- and enantioselective reactions possible.

The hemilabile behaviour of alkyl diphenylphosphinoacetate ligands promoting the reversible coordination of small molecules on (η6-arene)ruthenium(II) centres

Complexes [(μ6-arene){η1-Ph2PCH2CO)OR}RuCI2][arene = benzene, p-cymene, mesitylene or hexamethylbenzene; R = Me or tBu] have been prepared. Easy methanolysis and hydrolysis of the ester function occur when R = tBu. When R = Me, the stability of the ester function allows the synthesis of the stable salts [(η6-arene){η2-Ph2PCH2C(O)OMe}RuCl]X (X= PF6 or BF4). Preparation of [(η6-arene)(L){η1-Ph2PCH2C(O)OMe}RuCl]+ (L  Me2S, MeCN or tBuC N) from η1-P- and η2-(P,O)-methyl phosphinoacetate derivatives has been studied and the strength of both the L and ester ruthenium coordinative bonds compared. The reactivity of these functional phosphine complexes differs markedly from that of the homologous compounds [(η6- arene) (PMe3)RuCl2],[(η6-arene){P(OMe)3}RuCl2] and [(η6-arene){η2-Ph2PC(R)C(R ′)}RuCl. Competitive and reversible coordination of dimethylsulfide and nitriles or of the ester function is observed and a change in the arene produces selectivity in the coordination of dimethylsulfide and nitriles.

Ruthenium-catalyzed synthesis of functionalized 1,3-dienes.

Functionalized 1,3-diene derivatives have been prepared by regioselective allylation of various nucleophiles with 1,3-dienic carbonates in the presence of a (N,O-carboxylate) allylruthenium precatalyst.

A novel unsaturated (alkyne)titanium(II) complex (η5-C5H5)(η5-C5Me5)Ti(Ph–CC–Ph) and its coupling reaction with carbon dioxide

The titanium derivatives CpCp′TiX2(Cp η5-C5H5; Cp′=η5-C5Me5; X = Me, Ph, or CO) have been synthesized and the reaction of CpCp′Ti(CO)2 with diphenylacetylene and trimethylphosphine affords the unsaturated (alkyne)titanium(II) complex CpCp′Ti(C2Ph2) which readily adds carbon dioxide to give the metallacyclic compound [graphic omitted] via carbon-carbon bond formation.

First enantioselective allylic etherification with phenols catalyzed by chiral ruthenium bisoxazoline complexes.

Regio- and enantioselective substitution of cinnamyl chloride by phenols has been achieved with up to 82% enantiomeric excess, using a ruthenium catalyst prepared from [Cp*(CH(3)CN)(3)Ru][PF(6)] and a chiral bisoxazoline ligand.

DIALKYLSULFIDE)(ARENE)RUTHENIUM(II) DERIVATIVES

The preparations are reported of neutral and cationic (dialkylsufide)(η6-arene)ruthenium(II) complexes of the types (η6-arene)Cl2Ru(SR2), [(η6-arene)ClRu(SR2)2]+ and [(η6-arene)ClRu(SR2)(L)]+. These complexes containing labile R2SRu bonds can be used in the ready generation of 16 electron ruthenium moieties for the activation of terminal alkynes and access to cationic (carbene)(η6-arene)ruthenium(II) derivatives such as {(1,3,5-Me3C6H3)ClRu(SMe2)[C(OMe)CH2Ph]}+ and {(C6Me6)ClRu(PMe3)[C(OMe)CH2Ph]}+.

Complexes acetyleniques de titane(II). Reactivite vis-a-vis de l'hydrogene moleculaire: Une nouvelle approche du titanocene

Resume Electron-rich alkynetitanium(II) complexes Cp 2 Ti(PhCCPh)(PMe 3 ), (MeCp) 2 Ti(PhCCPh)(PMe 3 ) and Cp(C 5 Me 5 )Ti(PhCCPh) react with molecular hydrogen and are catalyst precursors for the hydrogenation of alkynes. Selective hydrogenation leading to cis -olefins takes place in the presence of an excess of PMe 3 under mild conditions (1 atm H 2 ).

A novel bifunctional bridging phosphinomethyl-alkoxycarbene ligand from (diphenylphosphinoacetylene)-ruthenium complexes

Abstract Some new neutral and cationic [HCC(Ph 2 )P](η 6 -arene)ruthenium(II) complexes have been prepared, namely (η 6 -arene)Cl 2 RuP(Ph 2 )CHCH and [(η 6 -arene(L)ClRuP(Ph 2 )CCH] + (L  PMe 3 , SMe 2 ). Activation of the terminal alkyne function allowed formation of unsymmetrical dinuclear derivatives in a process involving formation of a bridging phosphino-methoxycarbene ligand.