Diphenyl-1,3-butadiene

Submitted by Issei Iwai and Junya Ide1 Checked by James B. Sieja and Richard E. Benson 

spectrum (60 MHz., carbon tetrachloride solvent with t.ctramethylsilane as an internal reference) shows a complex multiplet centered at 431 Hz. attributable to the aromatic protons, and two doublets centered at 326 and 313 Hz., respectively, attributable to the olefinic protons. 

1 ( ommercially available dimethyl sulfoxide is freshly distilled in the presence of calcium hydride, b.p. 56-57° (5 mm.). 

2 Sodium hydride in oil (about 50%), available from Metal Hydrides I nc., Beverly, Massachusetts, was used. 

3 The formation of methylsulfinyl carbanion is essentially complete at this time. 

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Cyclotrithiazyl chloride is also a useful reagent in organic chemistry in the fusion of 1,2,5-thiadiazoles to quinones as well as the synthesis of (a) isothiazoles from 2,5-disubstituted furans and (b) bis-1,2,5-thiadiazoles from A-alkylpyrroles (Scheme 8.4). Alkenes and alkynes react readily with (NSC1)3 to give 1,2,5-thiadiazoles, while 1,4-diphenyl-1,3-butadiene gives a variety of heterocyclic products including a bis(l, 2,5-thiadiazole). ... 

Maleic anhydride is a convenient dienophile because of its rapid reaction with most dienes as well as its stability and ease in handling (although it is poisonous). The diene for this reaction, 1,4-diphenyl-1,3-butadiene, is readily prepared by the Wittig reaction with benzyltriphenylphosphonium chloride and cinnamaldehyde (Chapter 11, Section I). 

A lOO-ml round-bottom flask is charged with a mixture of xylene (25 ml), 1,4-diphenyl-1,3-butadiene (2.3 g), and finely powdered maleic anhydride (1.1 g). (Larger quantities may be used if desired as long as the reagents are equimolar.) The flask is... 

Fig. 22 Effect of zeolite enforced physical separation of substrate and sensitizer on product distribution in photooxygenation of 1,4-diphenyl-1,3-butadiene.

Diphenyl-1,3-butadiene, 40, 36 Diphenylcarbodiimide, 43,31 Diphenyl disulfide, set Phenyl disulfide Diphenyl ketimine, 44, 51 Diphenylmethylenimine, 44, 51 oe,j8-DlPHENYLPROPIONIC ACID, 40, 38 Dipotassium l, 8-naphthalenedicarbox-... 

Diphenyl-1,3-butadiene. The excited-state behavior of this diene differs significantly from stilbene and is the subject of a review. Unlike tS in which the lowest vertical excited singlet state is the 1 B state and S2 is the 2 Ag state in solution, these two excited states lie very close to each other in all-trans-1,4-diphenyl-1,3-butadiene (DPB). The additional carbon-carbon double bond introduces a new conformational equilibrium involving the s-trans and s-cis rota-mers. Most spectroscopic studies in solution have concluded that the l B state is S. The DPB compound has a low quantum yield for photoisomerization, so the use of DPB in time-resolved spectroscopic studies on photoisomerization, especially those that monitor only fluorescence decay, needs to be considered cautiously and critically. 

Several attempts to prepare palladium(II)-olefin complexes have failed. Thus, organosilicon groups from /3-trimethylsilylstyrene were cleaved (as chlorotrimethylsilane) by palladium(II) chloride (164) with formation of trans,tran.s-1,4-diphenyl-1,3-butadiene. 

In the vapor phase phenanthrene and hydrogen were products of the photolysis of c/.v-stilbene in addition to the expected mww-stilbene.65 The photolysis of 1,4-diphenyl-1,3-butadiene to give a-phenylnaphtha-lene is an analogous process.65 It was proposed that the intermediate dihydrophenanthrene was a cis form.66... 

The asymmetric dihydroxylation of dienes has been examined, originally with the use of NMO as the cooxidant for osmium [56a] and, more recently, with potassium ferricyanide as the cooxidant [56b], Tetraols are the main product of the reaction when NMO is used, but with K3Fe(CN)6, ene-diols are produced with excellent regioselectivity. The example of dihydroxylation of trans.trans-1,4-diphenyl-1,3-butadiene is included in Table 6D.3 (entry 21). One double bond of this diene is hydroxylated in 84% yield with 99% ee when the amounts of K3Fe(CN)6 and K2C03 are limited to 1.5 equiv. each. Unsymmetrical dienes are also dihydroxy-lated with excellent regioselectivity. In these dienes, preference is shown for (a) a bans over a cis olefin, (b) the terminal olefin in a,p,y,8-unsaturated esters, and (c) the more highly substituted olefin [56b],... 

In 1967, an original synthesis of 1,4-dilithio-1,4 diphenyl-1,3-butadiene (DDB) from 1,1-dimethyl-2,5-diphenylsilole (see equation 17 below) was proposed by Gilman and coworkers34. This dilithium reagent reacts with polyhalides R EX4 to yield 2,5-diphenylmetalloles (26, E = Si34,35, Ge36, Sn34) (Scheme 6). 

Complexes with 1,3-dienes. The reaction of activated Mg (11, 307) in THF at 25° with (E,E)-1,4-diphenyl-1,3-butadiene results in the deep red complex (1,4-diphenyl-1,2-butene-1,4-diylmagnesium). This halide-free bismagnesium reagent (1) forms a 1,4-adduct with a, co-dibromoalkanes, which undergoes intramolecular... 

The enthalpies of formation of solid (F)-stilbene and (E,E)- 1,4-diphenyl- 1,3-butadiene were taken from Reference 2 and that for (presumably) (F,F, )-l,6-diphenyl-l,3,5-hexatriene was taken from Reference 34a. 

In the classical oxidative alkyne-dimerisation reaction large quantities of solvent are often required which makes alternative procedures attractive. With 20 mol% CuCl and 20 mol% TMEDA, the dimerisation product of phenylacetylene, viz. 1,4-diphenyl-1,3-butadiene, was obtained at ambient temperature in [C4Ciim][PF6] in 95% y ield.1 2 Products were isolated by extraction of the ionic liquid phase with toluene and reuse of the catalyst was possible, but addition of further catalyst was necessary every two runs to keep reaction rates more or less constant. 

The preparation of 2-chlorothiopyrylium salts can be accomplished by a two-component synthesis. Reaction of /ru/ij-rra/i5-1,4-diphenyl-1,3-butadiene with excess thiophosgene gives 2-chloro-3,6-diphenylthiopyry-lium chloride 102 in high yield (Scheme 7) (67ZC227). The reaction probably consists in a Diels-Alder cycloaddition, followed by elimination of HCl and hydride abstraction. When the reaction was carried out with l-phenyl-3-methyl-l,3-butadiene, the 3,5-disubstituted thiopyrylium 103 was isolated without evidence of the 4,6-disubstituted regioisomer (84AP938). 

The reaction can also be carried out in ether if a donor ligand is added (triphenyl-phosphine or iri-n-butylphosphine). Yields of dimer are high if the alkenyl halide carries an electron-withdrawing group. Thus (ra s-2-bromoslyrene is converted into rra . ,rr[Pg.34]

C15H31l02Sn tributyltin-b-iodopropionate 73927-95-4 363.15 30.908 2 29114 C16H14 trans,trans-1,4-diphenyl-1,3-butadiene 538-81-8 625.15 56.029 1,2... 

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