Dimethylphenylphosphines, reaction with

When the initial vinylcarbene complex is substituted with a second me-thoxycarbonyl group (complex 169), a different reactivity pattern is observed. Addition of methyldiphenylphosphine or dimethylphenylphosphine to 169 results in formation of the expected vinylketene complex 170. However, the analogous reaction with triphenylphosphine yielded a complex mixture at room temperature, and upon heating the simple ligand-substituted product 171 is formed. When 169 is reacted with carbon monoxide, the pyrone complex 172 is formed. Finally, reaction of the vinylketene... 

Ignition on contact with furfuryl alcohol powdered metals (e.g., magnesium iron) wood. Violent reaction with aluminum isopropoxide -f- heavy metal salts charcoal coal dimethylphenylphosphine hydrogen selenide lithium tetrahydroaluminate metals (e.g., potassium, sodium, lithium) metal oxides (e.g., cobalt oxide, iron oxide, lead oxide, lead hydroxide, manganese oxide, mercur oxide, nickel oxide) metal salts (e.g., calcium permanganate) methanol + phosphoric acid 4-methyl-2,4,6-triazatricyclo [5.2.2.0 ] undeca-8-ene-3,5-dione + potassium hydroxide a-phenylselenoketones phosphorus phosphorus (V) oxide tin(II) chloride unsaturated organic compounds. 

The reaction of the phosphorane (70) with TDAP offers a convenient route to hexaphenylcarbodiphosphorane (73), which it has hitherto been difficult to prepare. Trimethylphosphine and dimethylphenylphosphine react with carbon tetrachloride in dichloromethane solution to form (74) and (75) the dichlorophosphoranes (74) are insoluble in the solvent, and evaporation of the filtrate affords the pure phos-phoranes (75). ... 

Metalations of various methylphosphines by BuLi-TMEDA were studied by Peterson (27) and by Rausch and Ciappenelli (II). Whereas methyldiphenylphosphine, for example, is inert to BuLi in hydrocarbon solvents, addition of an equivalent of TMEDA gives (diphenylphosphino)-methyllithium in 40-75% yield. Dimethylphenylphosphine and dimethyl-n-octadecylphosphine can also be converted into a-phosphinoalkyllithium compounds in similar yields with BuLi-TMEDA. The utility of these reagents as intermediates in synthesizing carbon functionally substituted phosphines was demonstrated by reactions with diphenylchlorophosphine, benzophenone, carbon dioxide, etc. 

Both dimethylphenylphosphine-borane (107) and -sulfide (108) are enantio-selectively deprotonated by a lithiumalkyl (—)-sparteine complex as demonstrated by subsequent reaction with electrophiles to give products with e.e. values of 80-87% (Scheme 8). Oxidative coupling of (109) in the presence of copper(II) pivalate gives the (S. S)-isomer (110) as the major product. Asymmetric metalla-tion and silylation of diphenylphosphinyl ferrocene (111) using the chiral lithium amide base derived from di(l-methylbenzyl)amine has been reported to give an... 

The (-)-enantiomer of sparteine is obtained from natural sources as a commercially available and relatively inexpensive oil. The metallation of 1 with n-BuLi in hexane, in the presence of (-)"Sp, produced the a-carbanion 2 which was subsequently quenched affording the known phosphine oxide 3 in approximately 14% ee. Although it has been suggested that the low stereoselectivity is due to the disruption of the (-)-sp/BuLi complex by complexation of the oxygen atom to the lithium cation, the same reaction with unprotected dimethylphenylphosphine provides completely racemic products. Due to the low enantioselectivity, this method was initially ignored in phosphorus chemistry until a seminal paper of Evans and co-workers in which they described similar reactions with phosphine boranes and sulfides. In this case, the enan-tioselectivities were much higher and the method could be successfully applied... 

The radical mediation of the thiol-ene reaction is brought about photochemically or via thermal decomposition of a radical initiator and the reaction is known to proceed by a radical mechanism to give a thioether, as shown in Fig. 12.31(A). Under nucleophile-initiated conditions, such as employing dimethylphenylphosphine (Mc2PPh, DMPP) as an initiator, the TEC reaction takes place extremely rapidly as well as quantitatively. The anionic chain mechanism proposed for the amine/phosphine mediated nucleophilic thiol-ene reaction with an acrylate is shown in Fig. 12.31(B). 

Some mechanistic speculation has been offered for reactions of trans-[ReOX3(PPh3)2], X = Cl or Br, with Schiff bases of the substituted salicyl-ideneimine type on the basis of preparative and spectroscopic data. The first step in the reactions of the rhenium(V) products of these reactions with dimethylphenylphosphine to give rhenium(III) species is simple displacement of PPh3 by PMe2Ph. Zirconium(IV) catalysis of substitution at the [ReFe] anion, containing inert rhenium(IV), is mentioned under osmium(IV) below. 

Two papers have appeared on the reactions of halogenophosphines with tervalent phosphorus compounds. In a detailed study of the reactions at 20 °C of a range of tertiary phosphines with phosphorus trichloride, dichlorophenylphosphine, and chlorodiphenylphosphine, it has been shown that, in general, 1 1 adducts are formed, provided that the tertiary phosphine is a good nucleophile. With diphenylchlorophosphine, for example, an adduct (18) is formed with dimethylphenylphosphine, but not with diphenylmethylphosphine, although the relative importance of steric and electronic factors remains to be established. The related reactions of phosphorus trichloride and of dichlorophenylphosphine are much more complex, and the initial crystalline products are not amenable to analysis. The reactions at 280 °C of a similar system have been shown to lead to halogen exchange, e.g. the conversion of (19) to (20). 

TaCl593 reacted with metallic sodium in neat trimethylphosphine to give the phosphinocarbene tantalum complexes 100 and 101, respectively. These reactions are the first examples of double activation of coordinated trimethylphosphine via oxidative cleavage of a substituent methyl C-H bond. A similar process was also observed in the reduction of tantalum pentabrom-ide with magnesium turnings in the presence of dimethylphenylphosphine.94... 

The procedure reported here involves a one-pot reaction of the inexpensive reagent K[FeH(CO)4], which is readily available from Fe(CO)s, with a stoichiometric quantity of a phosphane in a protic medium. It affords the complexes Fe(CO)2(PR3)3 or Fe(CO)2[P(OR)3]3 in fair to high yields using tributylphosphine, dimethylphenylphosphine, and trimethyl, triethyl, and... 

The second term, which outweighs the first one, is said to arise from an SN 2 contribution in the reaction mechanism. These observations have been taken as evidence in favour of the proposed -donating properties of acetonitrile,6 and it was stated that MeCN is as effective a nucleophile towards Mo(CO)6 as triphenylphosphine. The mww-labilizing properties of nitriles, on the other hand, are less pronounced than those of, for example, carbonyl or dimethylphenylphosphine. This is consistent with the weak -acceptor character of nitriles. 

Cationic methylplatinum(II)-nitrile complexes of the type m is-PtMeL2(NCR)+X have been isolated by the reaction of //vms-PtMeClL2, where L = dimethylphenylphosphine or trimethyl-arsine, with an aryl nitrile and AgX, where X = BF4, PF. Use of pentafluorobenzonitrile and 2,3,5,6-tetrafluorotetraphthalonitrile in alcohol has led to the synthesis of a series of imino ether complexes. A mechanism for imino ether formation, involving nucleophilic attack by an alcohol at a coordinated nitrile, is suggested and the course of the reaction is shown to be dependent not only on the alcohol but also on the size of the anion used.110... 

Dimethylphenylphosphine is a ligand commonly used to prepare a large range of transition metal-organophosphorus complexes. This basic phosphine is easy to handle and presents a small cone angle.1,2 It is usually prepared in 40-50% yield by reaction of a solution of methylmagnesium halide with phenylphosphonous dichloride followed by hydrolysis with an excess of saturated aqueous ammonium chloride solution.3 4 In the present preparation the yield has been greatly increased (to 85%). 

Dimethylphenylphosphine, (CH3)2CgHg.P. —One molecular proportion of zinc dimethyl in a large volume of benzene is treated with one molecular proportion of phosphenyl chloride in the same solvent, the mixture being cooled in ice and the air in the apparatus being replaced by carbon dioxide. The reaction takes place smoothly and two layers separate, the lower one containing the double compound of the base with zinc chloride. This layer is separated, the benzene removed, and the residue treated with sodium carbonate, then with solid potassium hydroxide several times. 

The reaction of the zero-valent osmium complex Os(CO)3(PPh3)2 with a series of strong acids (HX) has produced cationic hydrido-species of the type [Os(H)(CO)3(PPh3)2]X, where X = Br-, CIO4-, BF4-, or PF -. The complexes behave as 1 1 electrolytes in nitrobenzene and may be reconverted to the zerovalent complex on the action of base. Ammonia and primary amines (A) react with complexes of the type [MX3(PR3)3], where M = Os or Ru, in ethanol at 20 °C to form the M" species mer-[MX2(A)(PR3)a] and acetaldehyde. Secondary and tertiary amines with dimethylphenylphosphine ligands also cause reduction, but in this case the product is an alcohol complex. The reduction is considered to occur via formation of a hydride complex since some hydrogen is formed in all reactions and steric factors probably control whether an amine or an alcohol complex is formed. 

In the MBH type reaction of chiral non-racemic A-sulfinimines 210 with cyclopent-2-en-l-one we found that, in the presence of a catalytic amount of dimethylphenylphosphine (PhPMc2), a diastereoselective reaction could be achieved in toluene at room temperature to give the normal MBH adducts 211 in good yields with high diastereoselectivities (Scheme 2.106). ... 

An unusual cobalt-dioxygen adduct is formed in the reaction of O2 with [Co -(CN)a(PMe2Ph)3], in that during the course of reaction a dimeric complex is formed with the exclusion of only a single mole of dimethylphenylphosphine. The rate law of the form... 

---