Acetic phenyl phosphines

A novel route to indoles and quinolines has been developed by sequential Wiltig and Heck reactions <96CC2253>. Thus, treatment of o-bromo- or iodo-lV-lrifluoroaceiylanilines (86) with a stabilized phosphorane affords the corresponding enamines 87 as a mixture of isomers. Cyclization to 88 is effected by heating with palladium acetate, tri phenyl phosphine, and bu.se. 

Dimerization(46,47) with a palladium acetate/tertiary phosphine complex (di-ace tate-bis--[ tri-phenyl phosphine] palladium) in the absence of air gives primarily the desired linear dimer with smaller amount of branched, cyclic, and heavy product (Equation 13.). The reaction product is a complex mixture of cis and trans geometric isomers which makes analysis difficult. In order to simplify this problem, the product analysis is made after hydrogenation over 5% palladium on carbon. 

Chloro-(/7-cyanophenyl)phenylphosphine 349 Dichloro(phenyl)phosphine (60 g) is added to a slurry of i -cyanobenzenediazonium tetrafluoroborate (72 g) and copper(i) bromide (2.4 g) in dry isopropyl acetate (300 ml). After about 20 min a violent reaction sets in which is moderated by external cooling so that the temperature remains between 20° and 40°. When gas evolution ceases, aluminum turnings (8 g) are added and the mixture is stirred for 2 h at 40-50°. Then the liquid is decanted from unused aluminum, and phosphorus oxychloride (51 g) is added to decompose the aluminum chloride complex. Distillation then affords a forerun (5 g), followed by the main fraction (39 g, 47%) between 15870.7 mm and 195°/ 3.1 mm (owing to unavoidable decomposition the pressure does not remain constant during the distillation). Further distillation gives a product boiling at 16270.2 mm. 

For example, Mikolajczyk and Kielbasinski [172-175] studied the acylation of phosphine boranes 259 using CAL (Chirazyme ) lipase from Candida Antarctica and Lipase AK from Pseudomonas fluorescencs (Scheme 84). The best enantios-electivity was attained in the lipase AK-catalyzed acylation of 259 in cyclohexane solution with vinyl butyrate as an acyl donor (99% ee) for unreacted hydroxypho-sphinate 259 and 43% ee for the acylated product 260. The E-values were on the level of 15. The enzymatic resolution of alkoxy (hydroxymethyl)phenyl-phosphine boranes (/ /S)-261 was achieved by trans-esterification with vinyl acetate in the presence of CALB, Amano AK, Amano PS, Amano AH, and LPL in various solvents. The best enantioselectivity of imreacted alcohol 261 and acylated product 262 was attained in cyclohexane (37% ee, conversion 50%). Kielbasinski [176] recently reported some additional data, including theoretical calculations and more accurate chemical correlation, which proved that the borane reduction of acyclic phosphine oxides proceeded with inversion of configuration at the phosphoms center. On this basis, the stereochemistry of the enzymatic reaction was ultimately determined (Scheme 85). 

A flask was charged with 4-bromo-iodobenzene (0.079 mol), 4-methoxy-2-methyl-phenyl boronic acid (0.087 mol), palladium acetate (0.004 mol), and triphenyl phosphine (0.008 mol) and then treated with 200 ml acetone and 250 ml 2M NaHCO i. The mixture was refluxed at 65°C for 18 hours and was then treated with water and diethyl ether and the organic layer isolated. This layer was washed with 40 ml saturated sodium chloride solution and water, dried over MgSC>4, filtered, and concentrated. The residue was purified by column chromatography using silica gel with CH2C12/ hexane, 1 1, and then recrystallized in / , 7 3, respectively, and 16.4 g of product isolated. 

Z)-(2-Aminothiazol-4-yl)methoxyimino acetic acid Bis-(2-oxo-oxazolidinyl)phosphinic chloride 2-Mercapto-5-phenyl-l,3,4-oxadiazole... 

Transition Metal-Cataijrzed Reactions. Application of this ligand to the Pd-catalyzed ally lie alkylation of l,3-diphenyl-2-propenyl acetate with dimethyl malonate provides an alkylated product in >99.5% enantiomeric excess (eq 1). The enantiose-lectivity of the process is dependent on the ligand Pd ratio, the palladium precursor, and the nature of the nucleophile. Optimal conditions employed Pd(dba)s as the Pd precursor and 2 equiv of phosphine ligand, suggesting that two phosphines coordinate to the active Pd catalyst. Replacement of l,3-diphenyl-2-propenyl acetate with pent-3-en-2-yl acetate decreased the ee to 34% due to the reduced sterics of methyl relative to phenyl substituents. It is noteworthy that in contrast to this ligand, most monodentate ligands provide low enantioselectivity in this reaction. ... 

A number of methods were also developed for removing iodide impurities from acetic anhydride, such as syn-gas stripping [68], extraction in the presence of phenyl or alkyl phosphines [69], the use of lower fatty acids in combination with rhodium recovery [70], the use of silver-containing ion-exchangers [71], or oxidation with hydrogen peroxide [72]. 

Extension to aliphatic aldehydes leads to the 2,4,6-trialkyl-5-phenyl derivatives (342). When H3PO2 is refluxed in toluene with benzaldehyde or isobutyraldehyde the phosphinic acids (343 R = Ph, Pr ) are formed <68IZV397, 92EUP463994>. Di(hydroxymethyl)phosphines (344) react with aldehydes, ketones and acetals to form the 2-mono- or 2,2-disubstituted 1,3,5-dioxaphosphinanes (345) <86IZV2506,86ZOB2256>. With triethyl orthoformate the 2-ethoxy derivatives (346) are obtained (Scheme 70) <86IZV418, 86IZV640>. 

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