Phenylprop-l-ene

A number of biotransformations have been accomplished by rhodococci, including, for example, the hydrolysis of nitriles including polyacronitriles (Tauber et al. 2000), and the reduction of the conjugated C=C double bond in 2-nitro-l-phenylprop-l-ene (Sakai et al. 1985). 

The enantiomeric reduction of 2-nitro-l-phenylprop-l-ene has been studied in a range of Gram-positive organisms including strains of Rhodococcus rhodochrous (Sakai et al. 1985). The enantiomeric purity of the product depended on the strain used, the length of cultivation, and the maintenance of a low pH that is consistent with the later results of Meah and Massey (2000). It has been shown that an NADPH-linked reduction of a,p-unsaturated nitro compounds may also be accomplished by old yellow enzyme via the flcf-nitro form (Meah and Massey 2000). This is formally analogous to the reduction and dismutation of cyclic enones by the same enzyme (Vaz et al. 1995), and the reductive fission of nitrate esters by an enzyme homologous to the old yellow enzyme from Saccharomyces cerevisiae (Snape et al. 1997). 

Quenching with the bromide nucleophile gives the tertiary bromide. On the other hand, 3-phenylprop-l-ene is protonated to a secondary carbocation. In this case, rearrangement by hydride migration leads to a more favourable benzylic carbocation, and a benzylic bromide is the observed product. 

The reaction of phenyl-substituted alkenes (2-phenylprop-l-ene, ( )-l-phenylprop-l-ene, 1,1-diphenylethene, 1,1-diphenylprop-l-ene) with F-Teda BF4 (6) in the presence of various alcohols results in the formation of vicinal fluoro alkoxy adducts with Markovnikov-type regioselec-tivity.89,94 The stereochemistry of the fluorination-methoxylation addition reaction is slightly syn predominant in the case of (Z)-stilbene, indene, and dibenzosuberenone, while equal amounts of both diastereoisomers are formed in the case of ( )-l-phenylprop-l-ene and acenaphthylene. 

Dehydrobromination of 2,3-dibromo-l,l,l-trifluoro-3-phenylpropane (30) and 2-bromo-3,3,3-trifluoro-l-phenylprop-l-ene (31) leads to 3,3,3-trifluoro-1-phenylprop-1-yne (32).62... 

Researchers at Daikin Kogyo have reported that perfluorobut-2-ene (2a) can be obtained in 98% yield by passing but-l-ene la over alumina at 250 C.21,22 The isomerization of per-fluoro(3-phenylprop-l-ene) (Id) to 2d has also been achieved quantitatively with the DuPont catalyst aluminum chlorofluoride (ACF).14... 

The addition of elemental fluorine to (Z)- and ( )-l-phenylprop-l-ene occurs predominantly in a syn manner (Table 9, entries 1 and 2). 

Difluoro-2-phenylallylic amines such as 13 can be prepared in good to excellent yield by the treatment of 3,3,3-trifiuoro-2-phenylprop-l-ene (12) with N-lithiatcd amines. ... 

Trifluoro-2-phenylprop-l-ene (12 0.52 g, 3 mmol) was added at — 78 C over 2 min to LDA prepared from BuLi (2.5 M in hexanes, 1.36 mL) and diisopropylamine (0.56 mL, 3.5 mmol) in THF (20 mL). The pale yellow solution was stirred for 1 h and allowed to warm to 0 C over 1 h. The resulting brown mixture was then poured into sat. aq NH Cl. the layers were separated, and the aqueous phase was extracted with Et20 (3x50mL). The combined organics were dried and evaporated to afford a brown oil which... 

The results of the reactions involving these carbenes are compiled in Table 14. Irradiation of 5-diazo-10,l l-dihydrodibenzo[a,c/]cycloheptene with a high-pressure mercury lamp gives 10,11-dihydrodibenzo[a,rf]cyclohepten-5-ylidene, which can be trapped under the right conditions. When the photolysis was carried out in the presence of ( )-l-phenylprop-l-ene, stereospecific cycloaddition took place to give rra i-3-methyl-l-phenylspiro[cyclopropane-2,5 -10, lT-dihydro-5 //-dibenzo[a,cf]cycloheptene in 19% yield.Efficient trapping even on a synthetic scale is experienced when the diazo compound is irradiated in various styrenes. Thus, when 4-methoxystyrene was used as solvent l-(4-methoxyphenyl)spiro[cyclopropane-2,5 -10, lT-dihydro-5 7/-dibenzo[a,ii]cycloheptene (1) was isolated in 81% yield in addition 5,5 -bi(10,ll-dihydro-5//-dibenzo[u, f]cycloheptyl) (2) was obtained in 11% yield. 

A suspension of the sodium salt of 9-xanthone 4-toluenesulfonylhydrazone (1.25 g, 3.2 mmol) in anhyd EtjO (20 mL) and (Z)-l-phenylprop-l-ene (12.5 g, freshly distilled from NaH) in a Pyrex test tube (N purged, serum stopper sealed) was irradiated for 2.5 h at 25 "C with a 450-W Hanovia medium-pressure lamp. The sodium 4-toluenesulfinate formed was filtered and the (Z)-l-phenylprop-l-ene was removed in vacuo. The residue (0.56 g), on chromatography on silica gel eluting with hexane, gave 0.27 g (28%) of a 4 1 mixture of the cis- and /rani-isomers of the spirocyclopropane. 

Treatment of A-nitroso-iV-(cr5-2-phenylcyclopropyl)urea with excess sodium formate in methanol at 25 "C for 15 hours affords ( )-3-methoxy-l-phenylprop-l-ene (25%) and 3-methoxy-3-phenylprop-l-ene (60%, Table 15, entry 7). An almost identical result is obtained when the tran -isomer is used as substrate. Formation of the 2-phenylcyclopropyldiazonium ion, decomposition with loss of nitrogen to the 2-phenylcyclopropyl cation, followed by ring opening to form the phenylallyl cation, can explain the result. When [l- Hi]aminocyclopropane is subjected to deamination with nitrous acid in water at 0°C (Table 15, entry 8), allyl alcohol is obtained, which is isolated as the 4-(phenylazo)benzoate derivative in 44% yield. In this case, the deuterium is only located at the C2 allyl position. ... 

Synthesize 2-methyl-1-phenylprop-l-ene using a Wittig reaction. Begin by writing a retrosynthetic analysis. 

Bromo-l-phenylprop-l-ene shows a complex NMR spectrum in which the vinylic proton at C2 is coupled with both the Cl vinylic proton (/ = 16 Hz) and the C3 methylene protons (/ = 8 Hz). Draw a tree diagram for the C2 proton signal, and account for the fact that a five-line multiplet is observed. 

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