Triphenylphosphonium chloride

The resolution of racemic ethyl 2-chloropropionate with aliphatic and aromatic amines using Candida cylindracea lipase (CCL) [28] was one of the first examples that showed the possibilities of this kind of processes for the resolution of racemic esters or the preparation of chiral amides in benign conditions. Normally, in these enzymatic aminolysis reactions the enzyme is selective toward the (S)-isomer of the ester. Recently, the resolution ofthis ester has been carried out through a dynamic kinetic resolution (DKR) via aminolysis catalyzed by encapsulated CCL in the presence of triphenylphosphonium chloride immobilized on Merrifield resin (Scheme 7.13). This process has allowed the preparation of (S)-amides with high isolated yields and good enantiomeric excesses [29]. 

C22H32O3 15353-43-2) see Canthaxanthin (4-acetoxyretinyl)triphenylphosphonium chloride (04( 490102 15353-45-4) see Canthaxanthin 6-acetoxy-2,5,7,8-tctramethyl-2-(4-nitrophenoxymethyl>-4-chromanone... 

The solubility properties of Ni11 salen complexes can be varied by appropriate substituents. A choice of ligands containing /-butyl or methyl(triphenylphosphonium chloride) substituents at the aromatic rings (Figure 12) provides a series of Ni11 complexes with solubility adjustable for most commonly used solvents including water.1160... 

Benzotriazol-l-yl)methyl]triphenylphosphonium chloride 848 reacts with BunLi and aldehydes to give l-(alken-l-yl)benzotriazoles 849. Addition of bromine to the double bond of derivatives 849 followed by a reaction with amines furnishes amides 850. A variety of primary or secondary amines can be used. This way aldehydes are conveniently homologated and converted to amides with a one-atom longer chain (Scheme 136) <2004ARK(ix)44. 

The first attempt to prepare 2-phenyl-4-(phosphoranylidene)-5(4//)-oxazolone 219 started with l-benzoylamino-(2,2-dichloroethenyl)triphenylphosphonium chloride 216 and involved the complex reaction sequence shown in Scheme 7.67. The structure and properties of 219 were studied and it was shown that 219 underwent Wittig olefination with benzaldehyde to give the well-known (Z)-4-benzylidene-2-phenyl-5(477)-oxazolone. ... 

Xylylene-bis(triphenylphosphonium chloride), in synthesis of p-quin-quephenyl, 40, 86... 

A 100-mL round-bottomed flask containing a Teflon-coated magnetic stirring bar is charged with a solution of 0.69 g (1.5 mmol) of (pentafluorophenyl)(tetrahydrothiophene)gold(I) in 30 mL of ethanol 0.58 g (1.5 mmol) of (benzyl)triphenylphosphonium chloride (from Fluka AG) is added and the mixture is stirred at room temperature for 1 h. Concentration of the solution by removal of 20 mL of solvent under reduced pressure and cooling to 0 °C results in a white precipitate. This is separated by filtration and washed with two 5mL portions of hexane. Yield 0.94 g (83%). 

The phosphonium salts (58) were versatile reagents for the synthesis of 1,2,3-thiadiazoles (59) with unsaturated side chains. Ring closure of triphenylphosphonium chlorides (57) by the Hurd and Mori method gave these salts (58). Subsequent Wittig reactions did not occur stereoselectively. [95ZN(B)1121]... 

Thus, permethylated aldehydo sugars (6) have been found very susceptible to alkaline conditions, and suffer rapid /8-elimination, because of the acidity of the a-proton, with the formation of the enolic derivative (8) through a possible intermediate anion (7), as shown in equation 2. This phenomenon may explain the absence of interaction17 between the protected dialdose 9 and phenylenedimethylene-bis(triphenylphosphonium) chloride in the presence of lithium eth-oxide. Dialdose 9, indeed, is rapidly transformed18 in an alkaline medium into the unsaturated aldehyde 10 (see also, Ref. 19). Un-... 

Sodium hydride (45 mmol) was added to (ethoxycarbonylmethyl)-triphenylphosphonium chloride (45 mmol) dissolved in 112 ml THE, stirred 1 hour, and the product from Step 1 (24.9 mmol) dissolved in 60 ml THE added dropwise. After 1 hour the reaction was quenched with saturated 50 ml aqueous NH4CI, the crude products dissolved in diethyl ether, washed, dried, purified by flash chromatography on silica gel using hexane/EtOAc, 6.5 1, and the product isolated in 85% yield. 

To a hot (oil bath temperature 90 C), stirred solution of Ph3P (26.2 g, 0.1 mol) in anhyd benzene (110 mL) was added dropwise l-chloro-3-fluoropropan-2-one (5 ll.Og, 0.1 mol). After a while, the phosphonium chloride precipitated. At the end of the addition, stirring was continued at 90 C for 3 h. (1-Fluoro-acetonyl)triphenylphosphonium chloride (6) was filtered off from the cold mixture, washed with benzene, and dried under vacuum yield 28.7g (77%) mp 187 C (dec.). 

Cresp and Sargent also reported the preparation of the trifuran-containing annulenone 2.400c, a compound they prepared via two different Wittig-type pathways. The first of these involved the LiOEt catalyzed reaction between the 2,2 -bis-5 formylfuryl ketone 2.399 and the furan-2,5-bis(triphenylphosphonium chloride) 2.401. This produced the annulenone 2.400c in 8% yield (Scheme 2.3.28). The second approach involved simply switching the functionality present on the two precursors. Thus, the 2,5-bis(triphenylphosphonium chloride) species 2.405 was reacted with furan-2,5-dicarbaldehyde 2.359 yield to afford 2.400c in 9.6% yield. 

Caution. The vapor of 2-chlorobenzenamine is highly toxic, the liquid can also be absorbed through the skin. In addition, both anhydrous nickel chloride and dry (2-aminophenyl)triphenylphosphonium chloride tend to produce a fine dust when handled. It is recommended that procedures involving these materials be conducted in an efficient hood. 

A key step for the synthesis of prostaglandin Di methyl ester involves the reaction of dithiane (72) with (l-methylthiovinyl)triphenylphosphonium chloride (73 Scheme 44). ... 

Cyclopropylidenetriphenylphosphorane (1) reacts with alkyl chloroformates under mild conditions affording [l-(alkoxycarbonyl)cyclopropyl]triphenylphosphonium chlorides (2), the counterion being readily exchanged by treatment with sodium tetrafluoroborate. ... 

The bis-phosphonium salt (158) promotes the Lessen rearrangement of phenyl-hydroxamic acids and also brings about the Beckmann rearrangement of ketoximes under mild conditions. The salt (159), (formed from the reaction of 2-hydroxyethyl-triphenylphosphonium chloride with phosgene) has been employed as an amino-... 

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