Coupling reactions ruthenium®! chloride

Several metal cross-coupling reactions have been applied to pyrazoles. C-H Arylation of aryl tosylates or chlorides could be achieved with a ruthenium catalyst at the C-2 phenyl position of... 

Denmark pursued intramolecular alkyne hydrosilylation in the context of generating stereodefined vinylsilanes for cross-coupling chemistry (Scheme 21). Cyclic siloxanes from platinum-catalyzed hydrosilylation were used in a coupling reaction, affording good yields with a variety of aryl iodides.84 The three steps are mutually compatible and can be carried out as a one-pot hydro-arylation of propargylic alcohols. The isomeric trans-exo-dig addition was also achieved. Despite the fact that many catalysts for terminal alkyne hydrosilylation react poorly with internal alkynes, the group found that ruthenium(n) chloride arene complexes—which provide complete selectivity for trans-... 

Many ruthenium complexes have been tested in the silylative coupling reaction. In the synthetic procedure the absence of by-products of the homocoupling of vinylsilanes is required so an excess of the olefin has usually been used. However, the screening tests performed at the 1 1 ratio of styrene and phenyldimethylvinylsilane with a variety of ruthenium catalysts have shown that pentacoordinated monocarbonyl bisphosphine complexes appear to be the most active and selective catalysts of which RuHCl(CO)(PCy3)2 has shown high catalytic activity under conditions of catalyst loadings as low as 0.05 mol % [55]. Cuprous salts (chloride, bromide) have recently been reported to be very successful co-catalysts of ruthenium phosphine complexes, markedly increasing the rate and selectivities of all ruthenium phosphine complexes [54]. 

Dubbaka, S.R. and Vogel, P. (2005) Palladium-catalyzed desulfltative Mizoroki-Heck coupling of sulfonyl chlorides with mono- and disubstituted olefins rhodium-catalyzed desulfitative Heck-type reactions under phosphine- and base-free conditions. Chem. Eur. J., 11, 2633 1. Kamigata, N., Ozaki, J.-i., and Kobayashi, M. (1985) Reaction of alkenesulfonyl chlorides with olefins catalyzed by a ruthenium(ll) complex. A novel method for synthesis of ( , )- ,4-diaryl-... 

Rosenblum and cowoikers have described a number of routes to lace-to-lace polymetallocenes. Ruthenium- and iron-based materials were synthesized via palladium-catalyzed cross-coupling reaction of 1,8-diiodonaphthalene with metallo-cenylzinc chloride (M=Fe, Ru). The MW of the face-to-lace polyferrocenes with R=H,R = 2-octylwasintherangeof 18,000, while that of200 when R=R =2-octyl, was 139,000. The conductivity of polymer 200 (M=Fe, R=H, R =2-octyl) on doping with I2 was 6.7 X 10 S/cm. The incorporation of nickelocene and cobaltocene units into the fece-to-lace polyferrocenes resulted in materials with magnetic susceptibilities of 3.51 and 5.2 (1 for the Ni Fe and Co Fe ohgomers, respectively. ... 

A remarkable selective reaction involving first C-O bond formation followed by rearrangement and C-C bond formation occurred when Cp-containing ruthenium complexes were used as catalytic precursors. With RuCl(Cp)(PPh3)2 in the presence of NH4PF6, AgOTf or In(OTf)2 additives, which are known to facilitate chloride abstraction from the metal centre, the addition of allylic alcohols to terminal alkynes afforded unsaturated ketones [102, 103]. The key steps of this reconstructive coupling reaction are the nucleophilic addition of the allylic alcohol... 

The conventional synthesis of trans-2,5-dialkyl phospholanes starting from a chiral 1,4-diol is shown in Scheme 24.1. Originally, these 1,4-diols were obtained via electrochemical Kolbe coupling of single enantiomer a-hydroxy adds [25], but this method proved to be commercially impracticable and has since been replaced by more viable biocatalytic routes [26]. Reaction of the chiral 1,4-diol with thionyl chloride followed by ruthenium-catalyzed oxidation with so-... 

The synthesis of unsaturated compounds by C-C bond formation can also be carried out by coupling of alkenes with allenes, intermolecularly or intra-molecularly. Thus, 1,3-dienes were selectively obtained by coupling of allenes and vinyl ketones [28-30]. The reaction was catalyzed by the complex CpRuCl(COD) and with CeCl3 as a cocatalyst (Eq. 19). This cocatalyst is expected to decrease the chloride ion concentration to keep the active cationic ruthenium complex coordinatively unsaturated. 

Coupling of CM and intramolecular substitution to domino processes leading to tetrahydrofurans is feasible as well [38]. However, a corresponding combination to give tetrahydropyrans is better carried out as a sequential process [38d]. Reaction of the terminal olefin 184 with allyl chloride catalyzed by ruthenium complex 2 led to tetrahydrofuran 185 by a completely diastereoseleclive cyclization of the intermediate CM product (Scieme 2.65) [38a,b]. Compound 185 was then successfully advanced to the immunosuppressive diterpenoid pyrone subglutinol B. 

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