L-Phenyl-4-penten

We initially tested Candida antarctica lipase using imidazolium salt as solvent because CAL was found to be the best enzyme to resolve our model substrate 5-phenyl-l-penten-3-ol (la) the acylation rate was strongly dependent on the anionic part of the solvents. The best results were recorded when [bmim][BF4] was employed as the solvent, and the reaction rate was nearly equal to that of the reference reaction in diisopropyl ether. The second choice of solvent was [bmim][PFg]. On the contrary, a significant drop in the reaction rate was obtained when the reaction was carried out in TFA salt or OTf salt. From these results, we concluded that BF4 salt and PFg salt were suitable solvents for the present lipase-catalyzed reaction. Acylation of la was accomplished by these four enzymes Candida antarctica lipase, lipase QL from Alcaligenes, Lipase PS from Burkholderia cepacia and Candida rugosa lipase. In contrast, no reaction took place when PPL or PLE was used as catalyst in this solvent system. These results were established in March 2000 but we encountered a serious problem in that the results were significantly dependent on the lot of the ILs that we prepared ourselves. The problem was very serious because sometimes the reaction did not proceed at all. So we attempted to purify the ILs and established a very successful procedure (Fig. 3) the salt was first washed with a mixed solvent of hexane and ethyl acetate (2 1 or 4 1), treated with activated charcoal and passed into activated alumina neutral type I as an acetone solution. It was evaporated and dried under reduced... 

Although [BMIM]BF4 has been evaluated as an isolation medium for lipase-catalyzed biotransformations, the general experience with it has not been favorable, relative to that with other ionic liquids, such as [BMIM]PF6. However, excellent performance was recently reported for [BDMIM]BF4 when it was used to host Candida antarctica (Novozym 435) for the enantioselective transesterification of 5-phenyl-l-penten-3-ol (+ and -) with vinyl acetate. The working hypothesis was that the oligomerization of acetaldehyde may be caused by the C2 proton of the [BMIM] ion because of the unfavorable acidity of this group (226). In contrast, the cation in [BDMIM]BF4 lacks this acidity. 

A highly effective catalytic method for alkynylation of epoxides has recently been reported this involves the chelation-controlled alkylation of hetero-substituted epoxides with Mc3A1 and alkynyllithiums via pentacoordinate organoaluminum complexes [82]. For instance, reaction of epoxy ether, (l-benzyloxy)-3-butene oxide (75) in toluene with PhC = CLi under the influence of catalytic MesAl (10 mol%) proceeded smoothly at 0 °C for 5 h to furnish the alkynylation product l-(benzyloxy)-6-phenylhex-5-yn-3-ol (76) in 76 % yield. The yield of the product was very low (3 %) without MeaAl as catalyst under similar conditions. This is the first catalytic procedure for amphiphilic alkylation of epoxides. The participation of pentacoordinate MesAl complexes of epoxy ethers of type 75 is emphasized by comparing the reactivity with the corresponding simple epoxide, 5-phenyl-l-pentene oxide (77), which was not susceptible to nucleophilic attack of PhC s CLi with catalytic Me3Al under similar conditions (Sch. 50). 

Keto-5-phenyl-l-pentene, 572 Kharasch-Sosnovsky reaction, 66 Knoevenagel condensation, 342,507-508 Knorr pynole synthesis, 256-257 Koenigs-Knorr synthesis, 67... 

The lipase-catalysed enantioselective acylation of allylic alcohols in an ionic liquid solvent was demonstrated by Itoh et al. [16] (Fig. 7.7). They found that the acylation rate was strongly dependent on the counter anion of the imidazolium salt, while the lipase-catalysed acylation proceeded with high enantioseleclivity in all ionic liquid tested. Good results were obtained when the reaction was carried out in [bmimT [PFg ] or [bmun" ][BF ]. Other examples of kinetic resolution of allylic alcohols catalysed by lipases in ionic liquids were also reported by these authors [71, 72]. The transesterification of 5-phenyl-l-penten-3-ol under reduced pressure at 27 hPa and 40°C was carried out using methyl phenylthioacetate as acyl donor in [bmim+] [PF ] and [bdmim ][BF ], for obtaining the corresponding acylated compound in optically pure form [71], The acetylation of methyl mandelate catalysed by immobilised P5L in [bdmim ][BF ] is another example reported by these authors about the successful application of ionic liquids as reaction media in racemic resolutions... 

The intramolecular meta photocycloaddition of 5-phenyl-l-pentene derivatives has been applied very successfully by Wender and his group to the synthesis of a number of natural products. Some of their recent work in this area has been summarised in a paper based upon a lecture given at the Xlllth lUPAC Photochemistry Symposium. In addition, a communication has described the synthesis of the natural product subergorgic acid, (44), by a route which commences with intramolecular meta photocycloaddition of the phenylpentene... 

In contrast to the preferred meta mode of intramolecular photoaddition of 5-phenyl-l-pentenes, where the alkene and benzene groups are separated by three atoms, irradiation of the styrene (64) yields a single stereoisomer of the ortho adduct (65). In (64), not only are the reacting units separated by 4 atoms, but also it is the styrene rather than the benzene which is excited. Comparable photoreactivity is seen for phenanthrene-styrene systems such as (66) which yield 2+2 adducts (67) along with products derived from competing Paterno-Btichi reaction of the ester carbonyl with the alkene side chain. The photochemical cycloaddition also proceeds in an intermolecular fashion between the ester of 9-phenanthrene carboxylic acid and para-methoxy-0-methylstyrene. The mechanism of this reaction is shown to involve addition of the styrene to the singlet excited state of the phenanthrene derivative. °... 

COOH -> CO C C CrC C6H5COCH2CH2CH = CH2 A soln. of benzoic acid in tetrahydrofuran added at room temp, to a soln. in the same solvent of vinylmagnesium chloride prepared from Mg and gaseous vinyl chloride, agitated 4 hrs. at room temp. 5-oxo-5-phenyl-l-pentene. Y 84%. F. e. s. K. Suga et al.. Synthesis 1970, 189. 

Poly(l,4-pentadiene-alt-MA), 343, 348, 586 Poly(phenanthrene-alt-MA), 376, 660 Poly(phenylacetylene), MA grafted, 471 Poly(phenylacetylene-co-MA), 335, 660 Poly(2-phenylallyl alcohol-alt-MA), 331, 660 Poly(4-phenyl-l-butene-alt-MA), 340, 341 Poly(/- 1-phenylethyl methacrylate-co-MA), optically active polymer, 383 Poly(/-1-phenylethyl vinyl ether-alt-MA), optically active polymer, 383 Poly(5-phenyl-l-pentene-alt-MA), 340, 341 Poly( l-phenyl-4-pentene- 1-one-alt-MA), 314 Poly(3-phenyl propene-l-alt-MA), 341 Poly(o-phenylstyrene-alt-MA), 373 Poly(2-phenylvinyl alkyl ethers-alt-MA), 318 Poly(2-phenylvinyl alkyl thioethers-alt-MA), 318 Poly(phenyl vinyl ether-alt-MA), 318, 394 Poly(phenyl-o-vinyl formal-alt-MA), 328 Poly(phenyl vinyl ketone-co-MA), physical properties, 290... 

Pillsbury, N., and T.S. Zwier. 2009. Conformation-specific spectroscopy and excited state photophysics of 5-phenyl-l-pentene. 7. Phys. Chem. 113A 118-125. 

The addition of methyllithium to -alkoxy-a-(trimethylsilyl)-of/ unsaturated sulfones, 3-alkoxy-5-phenyl-l-phenylsulfonyl-l-(trimethylsilyl)-l-pentene and subsequent desilylation gives syn-products. The syn to anti diastereoselectivity is generally high and essentially independent of the nature of the y-alkoxy substituent8-13. 

Cathodic reduction of 1,3-diphenyl-propenone leads to l-hydroxy-2-benzoyl-3,4-diphenyl cyclopentanes with exclusive cis configuration of the two phenyl groups. With l-phenyl-l-pentene-3-one the cyclodimer 2-methyl-3,5-diphenyl-4-(l-propionyl)-cyclohexanone is formed with a 100% yield in an intramolecular Michael addition via an electrogenerated base. The substituents are all in the most stable equatorial position [277]. 

Mit dem gleichen Reagenz erhalt man z. B. aus N-Propyl-benzaldimin erythro-4-Methyl-5-phenyl-5-propylamino-l-penten (75%) und aus N-Benzyl-benzaldimin 5-Benzylamino-4-methyl-5-phenyl-1-penten (90% erythro threo = 8 92)2 analog erhalt man aus 2-Phenyl-propanal-isopropylimin mit 9-Allyl-9-bora-bicyclo[3.3.1]nonan erythro-4-Isopropylamino-5-phenyl-l-hexen ( 90%)1. 

Pentene 2-(Benzvl-methyl-ainino)-5-phenyl-l. 1.1 -irifluoro- ElOb, 459 (FjC - CO - NR, +... 

For example, irradiation of ( )-iV-isopropyl-5-phenyl-4-pentenamine (0.01 M in acetonitrile purged with nitrogen) in a Rayonet reactor fitted with RPR 3000 lamps for 15 minutes (>95% conversion) results in the formation of A -isopropy 1-2-phenyl piperidine (65% yield) and 5-phenyl-4-pentenal (15%), whereas irradiation of the A-Zert-butyl compound resulted in quantitative formation of the imine28. cis Selective N-D addition was observed in the cyclization of (ZO-Af-deuterio-Af-methyl-S-phenyl-d-pentenamine [( )-l], but from the (Z)-isomer [(Z)-l] the cis/trans ratio was 3 1 28,66, since rotational equilibration of the biradical intermediate is faster than cyclization. 

The photoreaction of l,l-dicyano-2-phenylefliene with allylsilane in the presence of phenanthrene in acetonitrile affords 5,5-dicyano-4-phenyl-l-pentene in good yield. Phenanthrene acts as a redox sensitizer in this process and allylation occurs at the position P to the cyano group. On the other hand, a similar photoallylation reaction of cyclo-... 

Epoxy-l,3,5-cyclooctatriene added dropwise with ice-cooling to a soln. of propynylmagnesium bromide prepared from propyne and ethylmagnesium bromide in abs. ether, stirred 2 hrs. at room temp, and 1 hr. under reflux -> l-(2,4,6-cycloheptatrien-l-yl)-2-butyn-l-ol (Y 75%) dissolved in dimethylformamide, ice-cooled, treated dropwise with a soln. of SOClg in dimethylformamide, and stirred 1 hr. at room temp. l-phenyl-l-penten-3-yne (Y 87%). F. e. s. J. Hambredit, H. Straub, and E. Muller, B. 107, 2985 (1974). 

Apolit, Ann, chim., 1924, 2,102. 2>Methyl-5-phenyl-2-pentene (l-PkenyU... 

Ciardelli et al [170] obtained similar results with stereoregular homo- or copolymerization with 4-methyl-1-pentene, of OA phenyl-a-olefins such as (/ )-4-phenyl-a-hexene (LXVIa) and ( S )-5-phenyl-l-heptene (LXVIb) in the presence of TiCls or VCI4/aluminum triisobutyl catalyst which is known for not producing any racemization. 

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