Butene trans--phenyl

Bei der Hydroaluminierung von Alkinen tritt die Oligomerisierung oft bereits bei nied-rigeren Temperaturen in den Vordergrund. So erhalt man z.B. aus 3,3-Dimethyl-l-phe-nyl-butin (I) und Bis-[2-methyl-propyl]-aluminiumhydrid (1 1) bei 50° 94% d.Th. cis-3,3-Dimethyl-l-phenyl-buten-(l) (II)5 neben 6% d.Th. trans,trans-2,2,7,7-Tetramethyl-4,5-diphenyl-octadien-(3,5) (III) ... 

Table 3 summarizes the scope and limitation of substrates for this hydrogenation. Complex 5 acts as a highly effective catalyst for functionalized olefins with unprotected amines (the order of activity tertiary > secondary primary), ethers, esters, fluorinated aryl groups, and others [27, 30]. However, in contrast to the reduction of a,p-unsaturated esters decomposition of 5 was observed when a,p-unsaturated ketones (e.g., trans-chalcone, trans-4-hexen-3-one, tra s-4-phenyl-3-buten-2-one, 2-cyclohexanone, carvone) were used (Fig. 3) [30],... 

Ordinary Grignard reagents react with a, -unsaturated carbonyl compounds and afford both 1,2-adduct and 1,4-adduct. However, methylsulfonyhnethylmagnesium bromide or p-tolylsulfonylmethylmagnesium bromide gave only 1,2-adducts in the reaction with conjugated carbonyl compounds such as crotonaldehyde, cinnamaldehyde, trans-4-phenyl-3-buten-2-one, benzalacetophenone and l,5-diphenyl-2,4-pentadien-l-one. 

An interesting gas-phase study of the photolysis of ftmy-l-phenyl-2-butene has been published by Comtet.(39,40) He has found that (a) it was not possible to quench the formation of the cyclopropane product under conditions that reduced the fluorescence quantum yield, (b) sensitization by acetophenone only gave cis-trans isomerization, and (c) the quantum yield of cyclopropane formation in the direct photolysis decreases as n-butane is added to the reaction mixture. Comtet suggests that the data are consistent with a reaction from the second triplet state. 

The disilanickela complex 21 was also found to be a good catalyst for the dehydrogenative double silylation of aldehydes. The nickel-catalyzed reactions of 1,2-bis(dimethylsilyl)carborane 11 with aldehydes such as isobutyraldehyde, trimethylacetaldehyde, hexanal, and benzaldehyde afforded 5,6-carboranylene-2-oxa-l,4-disilacyclohexane.32 34 36 The dehydrogenative 1,4-double silylation of methacrolein and tram-4-phenyl-3-buten-2-one in the presence of a catalytic amount ofNi(PEt3)4 also took place under similar conditions. In contrast, the reaction of 11 with a-methyl-tran.s-cinnamaldehyde and irans-cinnamaldehyde under... 

A single chloro compound, trans-1 -phenyl-3-chloro-1 -butene (7), is formed in hydrochlorination of isomeric 1-phenyl-1,3-butadienes in AcOH135 (Scheme 6.2). The observation is interpreted by the formation of different isomeric allylic carbo-cations (6c and 6t). Rapid rotation of 6c to 6t before captured by the chloride ion ensures selective formation of 7. 

Pheny1-1,3-butadione, AR53 trans-U-Phenyl-3-buten-2-one,... 

In nonprotic solvents, alkenes are stoichiometrically oxidized by Vv-peroxo complexes to epoxides and consecutive oxidative cleavage products in a nonstereoselective fashion. For example, cis-2-butene gave an approximately 2 1 mixture of cis- and trans-epoxides (equation 37). The reactivity of alkenes increases with their nucleophilic nature. Alkenes containing phenyl substituents such as styrene, a- and jS-methylstyrene are also very reactive and mainly give oxidative cleavage products. 

Truce and collaborators (7-9) have shown that cis-dichloroethylene 20 reacts readily with sodium -toluenethiolate in the presence of sodium ethoxide to give cis-1,2-bis-p-tolylmercapto-ethylene 22 while the trans-isomer 21, when subjected to the same conditions is recovered unchanged. Convincing evidence was obtained that the conversion 20 22 takes place via the intermediates 23, 24, and 25. Truce and Simms (9) have also observed that the base-catalyzed addition of -toluenethiol to phenyl acetylene and to 2-butyne yields ci s-styryl -tolylsulfide (26) and 2-p-tolylmercapto-trans-2-butene (27) respectively. 

Ghanem, A. Schurig, V. Lipase-catalyzed access to enantiomerically pure (R)- and (S)-trans-4-phenyl-3-butene-2-ol. Tetrahedron Asymmetry 2003, 14, 57-62. 

The lack of reactivity of the aryloxazolinones (65) in photocycloaddition to many of the olefins other than 1,1-dimethoxyethene and furan probably results from efficient decay of E2 or D. Exciplex E2 and diradical D are proposed as intermediates in these cases for several reasons. Exciplex formation is most likely dependent on olefin ionization potential, and the ionization potential of many of the un-reactive olefins are intermediate between the ionization potential of furan and 1,1-dimethoxyethene as determined from the maxima of tetracynoethylene olefin charge transfer bands60 66,67. Although ds-2-butene does not form a cycloadduct with 2-phenyl-2-oxazolin-4-one (65a), ds-2-butene is isomerized to rram-2-butene during the irradiation52. Cis-trans isomerization is expected from decay of a triplet diradical. Decay of the exciplex and diradical intermediates in competition with reaction presumably results from steric hindrance from the aryl substituent. The olefins which give cycloadducts, furan and 1,1-dimethoxyethene, are expected to produce low steric hindrance with the aryl substituent in an exciplex or diradical. 

This review will illustrate examples of computer projected models of inclusion complexes of structural isomers (ortho, meta, para nitrophenol), enantiomers (d- and 1- propranolol) and diastereomers [cis and trans. l(p-B-dimethylaminoethoxy-phenyl-butene), tamoxifen] in either a- or B-cyclodextrin. The use of these computer projections of the crystal structures of these complexes allows for the demonstration and prediction of the chromatographic behavior of these agents on immobilized cyclodextrin. 

Typical reactions in this category occur with 1-chloro-2,4-dinitrobenzene, 1,2-chloro-4-nitrobenzene, ethacrynic acid, trans-4-phenyl-3-buten-2-one and a range of hydroxylated derivatives of polycyclic hydrocarbons. 

A 500-mL, three-necked, round-bottomed Mask is equipped with a mechanical stirrer, nitrogen inlet adapter, and 150-mL pressure-equalizing dropping funnel fitted with a rubber septum (Note 1). The flask is charged with 70 mL of dry tetrahydrofuran (Note 2) and 15.9 mL (0.075 mol) of 1,1,1,3,3,3-hexamethyldisilazane (Note 3), and then cooled in an ice-water bath while 28.8 mL (0.072 mol) of a 2.50 M solution of n-butyllithium in hexane (Note 4) is added dropwise over 5-10 min. After 10 min, the resulting solution is cooled at -78°C in a dry ice-acetone bath, and a solution of 10.0 g (0.068 mol) of trans-4-phenyl-3-buten-2-one (Note 5) in 70 mL of dry tetrahydrofuran is added dropwise over 25 min. The dropping funnel is washed with two 5-mL portions... 

Starting from allylic and homoallylic amines7-8, iodocyclocarbamation occurs with high stereocontrol and 1,2-asymmetric induction only if bulky groups are involved. Thus. 3-/er/-butoxy-carbonylamino-4-phenyl-l-butene (1, R = H), readily obtained from ethyl (R)-A -Boc-phenyl-alanate, cyclizes upon treatment with 3 equivalents of iodine in dichloromethanc to afford a mixture of trans- and cw-4-benzyl-5-iodomethyl-2-oxazolidinone (2) in a 60 40 ratio. Better results are obtained when a bulky group, such as an iY-benzyl group, is introduced. 

C10H9NO2 methyl indole-3-carboxylate 942-24-5 25.00 1 2355 2 19104 C10H10O trans-4-phenyl-3-buten-2-one 1896-62-4 45.00 1.0097 1... 

Use of aluminum-based bidentate Lewis acid 14 results in unique stereoselectivity in the Michael addition of KSA (Scheme 10.84) [37[. The 14-promoted reaction of the KSA derived from mefhyl isobutyrate wifh 4-phenyl-3-buten-2-one gives fhe corresponding E adduct selectively, in contrast wifh fhe 15-promoted reaction, which is Z-selective. The origin of fhe inverse selectivity is probably that 14 forces the enone to take fhe s-trans formation 92 by double coordination of the carbonyl oxygen. 

S,S-trans-2-butene (tbn) or S-2-methyl-2-butene (mbn) as a source of asymmetry and other ligands including L-prolinate, 4-substituted anilines and 4-substituted pyridines. Among them [PtCl(o-phenyl-enediamine)(S-mbn) ] is the first optically active square planar complexes with positive charge. The CD data are given in Table II. 

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