Diphenylphosphinoethane

Fig. 7. Representive stmctures for compounds of molybdenum(0) (a) Mo(CO)g (b) tris(acetonitrile)tris(carbonyl)molybdenum(0) (c) bis(l,2-diphenylphosphinoethane) bis (dinitrogen) molybdenum(0), [R2PCH2CH2PR2]2Mo(N2)2, where R = CgH, also known as Mo(dppe)2(N2)2, where dppe = 1,2 — diphenylphosphinoethane (d) cyclopentadienyl tricarbonyl molybdenum(0) anion, CpMo(CO)3, where Cp = cyclopentadienyl (e)...

Abbreviations aapy, 2-acetamidopyridine Aik, alkyl AN, acetoniuile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene COE, cyclooctene COT, cyclooctatetraene Cp, cyclopentadienyl Cp , penta-methylcyclopentadienyl Cy, cyclohexyl DME, 1,2-dimethoxyethane DME, dimethylformamide DMSO, dimethyl sulfoxide dmpe, dimethylphosphinoethane dppe, diphenylphosphinoethane dppm, diphenylphosphinomethane dppp, diphenylphosphinopropane Et, ethyl Ec, feirocenyl ind, inda-zolyl Me, methyl Mes, mesitylene nb, norbomene orbicyclo[2.2.1]heptene nbd, 2,5-norbomadiene OTf, uiflate Ph, phenyl PPN, bis(triphenylphosphoranylidene)ammonium Pi , propyl py, pyridine pz, pyrazolate pz, substituted pyi azolate pz , 3,5-dimethylpyrazolate quin, quinolin-8-olate solv, solvent tfb, teti afluorobenzobaiTelene THE, tetrahydrofuran THT, tetrahydrothiophene tmeda, teti amethylethylenediamine Tol, tolyl Tp, HB(C3H3N2)3 Tp , HB(3,5-Me2C3HN2)3 Tp, substituted hydrotiis(pyrazol-l-yl)borate Ts, tosyl tz, 1,2,4-triazolate Vin, vinyl. 

Rhodium, hexakis(trifluorophosphine)di-, 4, 905 Rhodium, hydridobis(diphenylphosphinoethane)-, 4, 924 Rhodium, hydridotetrakis((butylidynetrimethylene)-phosphite)-, 4, 921... 

For trisubstituted olefins, the nucleophile attacks predominantly at the less substituted end of the allyl moiety, e.g. to afford a 78 22 mixture of 13 and 14 (equation 7). Both the oxidative addition of palladium(O) and the subsequent nucleophilic attack occur with inversion of configuration to give the product of net retention7. The synthesis of the sex pheromone 15 of the Monarch butterfly has been accomplished by using bis[bis(l,2-diphenylphosphinoethane)]palladium as a catalyst as outlined in equation 87. A substitution of an allyl sulfone 16 by a stabilized carbon nucleophile, such as an alkynyl or vinyl system, proceeds regioselectively in the presence of a Lewis acid (equation 9)8. The... 

Figure 22 shows the molecular structure of [W( 2-C60)(CO)3(dppe)] (dppe = 1,2-diphenylphosphinoethane) together with its cyclic voltam-metric response.37... 

Success was obtained with Ru3(CO)i2 as catalyst precursor [6], but the most efficient catalysts were found in the RuCl2(arene)(phosphine) series. These complexes are known to produce ruthenium vinylidene spedes upon reaction with terminal alkynes under stoichiometric conditions, and thus are able to generate potential catalysts active for anti-Markovnikov addition [7]. Similar results were obtained by using Ru(r]" -cyclooctadiene)(ri -cyclooctatriene)/PR3 as catalyst precursor [8]. (Z)-Dienylcarba-mates were also regio- and stereo-selectively prepared from conjugated enynes and secondary aliphatic amines (diethylamine, piperidine, morpholine, pyrrolidine) but, in this case, RuCl2(arene) (phosphine) complexes were not very efficient and the best catalyst precursor was Ru(methallyl)2(diphenylphosphinoethane) [9] (Scheme 10.1). 

Other classical ligands such as triphenylphosphine or 1,2-diphenylphosphinoethane have been considered. However, no good results were obtained under these conditions since a mixture of ArH and ArAr was produced. Moreover, the use of acetonitrile as solvent does not lead to positive results. In addition to the above-described general case, some particular cases have been examined, such as in the presence of bromothiophene. 

Lactone synthesis.2 Carbonylation of simple organic halides can be carried out readily with several palladium catalysts such as bis(diphenylphosphinoethane)-his(triphenylphosphine)palladium(0) and dichlorobis(triphenylphosphinc)pal-ludium(ll). The latter catalyst is preferred because it is stable and easily converted to Pd(0) in situ. Carbonylation of halo alcohols provides a useful synthesis of various lactones. 

Methyl-2-propenyl-3-methyl-3-butenoate and 2-methyl-2-propenyl-3-methyl-2-butenoate may be produced by the stoichiometric reaction of dichlorobis(2-methyl allyl)bis(diphenylphosphinoethane) dipalladium (31) with carbon dioxide in acetonitrile (113) [Eq. (43)], to give an overall 45% yield of the esters. 

P-31 NMR studies also were carried out in a similar manner on rhodium complexes of two chelating bisphosphines—bis-l,3-diphenyl-phosphinopropane and bis-l,2-diphenylphosphinoethane. These complexes were generated in solution via ligand displacement from tris(tri-phenylphosphine)rhodium carbonyl hydride. For example, one of the possible displacement products of bis-l,3-diphenylphosphinopropane (F) is a cis-chelate (G) that can undergo dissociation to yield a chelating bisphosphine complex (H) ... 

As indicated in the introduction, bis-l,3-diphenylphosphino-propane (dppp) and bis-l,2-diphenylphosphinoethane (dppe) were reacted with tris(triphenylphosphine)rhodium(II) carbonyl hydride in toluene-deuterobenzene solution to derive cis-chelate complex hydroformylation catalysts. These complexes were expectedly non-selective terminal hydroformylation catalysts for 1-butene hydroformylation (see Table I) because of their cis-stereochemistry. They were also somewhat less active due to their specific structural features. The structure of these complexes in solution was studied in detail by P-31 NMR spectroscopy. 

A nickel hydride complex, NiHCl(diphenylphosphinoethane), catalyses the tandem isomerization-aldolization reaction of allylic alcohols with aldehydes.156 The atom- (g) efficient process proceeds at or below ambient temperature with low catalyst loading, and works well even for bulky aldehydes. Magnesium bromide acts as a co-catalyst, and mechanistic investigations suggest that a free enol is formed, which then adds to the aldehyde in a hydroxyl-carbonyl-ene -type reaction. 

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