Phosphine-sulfoxide, complex

This chapter reports principally on studies with ruthenium chiral phosphine and chiral sulfoxide complexes and their use for catalytic hydrogenation. We have used the familiar diop ligand, [2R,3R-(—)-2,3-Oisopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino) butane] (7) a related chiral chelating sulfoxide ligand dios, the bis(methyl sulfinyl)butane analog (21) (S,R S,S)-(+)-2-meth-ylbutyl methyl sulfoxide(MBMSO), chiral in the alkyl group and R-(+)-methyl para-tolyl sulfoxide(MPTSO), chiral at sulfur. Preliminary data on some corresponding Rh(I) complexes are presented also. 

The P=0 —> Sn bonds in phosphine oxide complexes (Table 24) are somewhat shorter than those found in the same carbonyl (Table 23), sulfoxide (Table 25) and A-oxide (Table 26) complexes, reflecting the greater Lewis basicity of the former. 

CCC (1987) contains a section on sulfoxides, amide, amine oxides, and related ligands that have sections on phosphine oxides and arsine oxides.159 Phosphine and arsine oxide complexes of yttrium and the lanthanides were highlighted in CCC (1987).1 Scandium and yttrium phosphine oxide complexes have been reinvestigated and characterized by multinuclear NMR and X-ray... 

Platinum square planar complexes Alkenes, allenes, arsines, phosphines, sulfoxides, cyclic ethers, etc. [49,50]... 

Coordination of mercurial species is certainly involved in several of these processes. Although the strictly inorganic compounds of mercury form well-defined coordination complexes with amines, phosphines, sulfoxides, phosphine oxides, and amine oxides, particularly when a noncoordinating gegenion for mercury is employed, coordination numbers up to six having been observed (56), the coordination chemistry of organometallic derivatives of mercury is just developing (87-89). 

Lewis bases, complex and simple anions, carbanions, amines, oxides, sulfurs, phosphines, sulfoxides, ketones, ethers, alcohols. 

Arylation of chalcones Ar CH=CHCOAr with Ar B(OH)2, catalysed by the Rh complex of phosphine-sulfoxide (514a), has been reported to proceed with <98% ee at 40 C in aqueous i-PrOH and with KF added. " 1... 

The reaction described by Eq. 5.8, in which the chloride ligands of [PtCl2(PhCN)2l are replaced while the benzonitrile ligands are unaffected, may be contrasted with the more common mode of reactivity for this complex in which the labile benzonitrile ligands undergo fadle substitution, not only by neutral ligands such as tertiary phosphines, sulfoxides, etc., but also by anions, such as the chloride ion,33 Eq. 5.9 ... 

The reaction of alcohols with CO was catalyzed by Pd compounds, iodides and/or bromides, and amides (or thioamides). Thus, MeOH was carbonylated in the presence of Pd acetate, NiCl2, tV-methylpyrrolidone, Mel, and Lil to give HOAc. AcOH is prepared by the reaction of MeOH with CO in the presence of a catalyst system comprising a Pd compound, an ionic Br or I compound other than HBr or HI, a sulfone or sulfoxide, and, in some cases, a Ni compound and a phosphine oxide or a phosphinic acid.60 Palladium(II) salts catalyze the carbonylation of methyl iodide in methanol to methyl acetate in the presence of an excess of iodide, even without amine or phosphine co-ligands platinum(II) salts are less effective.61 A novel Pd11 complex (13) is a highly efficient catalyst for the carbonylation of organic alcohols and alkenes to carboxylic acids/esters.62... 

The red and orange forms of RhCl[P(C6H5)3]3 have apparently identical chemical properties the difference is presumably due to different crystalline forms, and possibly bonding in the solid. The complex is soluble in chloroform and methylene chloride (dichloromethane) to about 20 g./l. at 25°. The solubility in benzene or toluene is about 2 g./l. at 25° but is very much lower in acetic acid, acetone, and other ketones, methanol, and lower aliphatic alcohols. In paraffins and cyclohexane, the complex is virtually insoluble. Donor solvents such as pyridine, dimethyl sulfoxide, or acetonitrile dissolve the complex with reaction, initially to give complexes of the type RhCl[P(C6H6)3]2L, but further reaction with displacement of phosphine may occur. 

Henbest and Mitchell [78] have shown that water can be used as hydrogen source with chloroiridic acid (6) as the catalyst through oxidation of phosphorous acid (59) to phosphoric acid (60) in aqueous 2-propanol. Under these conditions, no hydrogen transfer occurs from 2-propanol. However, iridium complexes with sulfoxide or phosphine ligands show the usual transfer from 2-pro-panol [79-81]. 

Several reports have appeared on the effect of additives on the Pauson-Khand reaction employing an alkyne-Co2(CO)6 complex. For example, addition of phosphine oxide improves the yields of cyclopentenones 119], while addition of dimethyl sulfoxide accelerates the reaction considerably [20]. Furthermore, it has been reported that the Pauson-Khand reaction proceeds even at room temperature when a tertiary amine M-oxide, such as trimethylamine M-oxide or N-methylmorpholine M-oxide, is added to the alkyne-Co2(CO)6 complex in the presence of alkenes [21]. These results suggest that in the Pauson-Khand reaction generation of coordinatively unsaturated cobalt species by the attack of oxides on the carbonyl ligand of the alkyne-Co2(CO)6 complex [22] is the key step. With this knowledge in mind, we examined further the effect of various other additives on the reaction to obtain information on the mechanism of this rearrangement. 

Trisubstituted alkenes.9 A stereoselective synthesis of trisubstituted alkenes uses (E)-alkenyl sulfoxides (1)>U as the starting material. These are reduced to the corresponding sulfides (2)," which undergo coupling with Grignard reagents in the presence of complexes of nickel chloride and phosphines as catalyst.12 The products (3) are obtained in steroisomeric purity of > 99%. 

Table 28 Complexes of Dimethyl Sulfoxide and Phosphine and Arsine Oxides...

Amine A-oxides, phosphine oxides and other phosphoryl compounds and analogous arsenic derivatives, and sulfoxides all give well-defined complexes with scandium. In many cases, authors deal with several of these classes of ligand in the same paper, so it will be most convenient to consider them together here. 

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