1,1 -Diphenyl-1,3-pentadiene

Die Reduktion von 2,4-Dibrom-3-oxo-l,5-diphenyl-pentadien-(l,4) an Quecksil-ber/Dimethylformamid /Tetramethylammoniumperchlorat bei -1,1 Volt fiihrt zu 3-Oxo-1,5-diphenyl-penten-(4)-in-(l) 6 ... 

Einen Dberbliek iiber die sterisehen Verhaltnisse, in die auch w-[Pg.227]

Benzoylamino-4-(3,4-dimethoxy-phenyl)-buten-(3)-saure 5-Oxo-l, 5-diphenyl-pentadien-( 1,3) 4,4 -Dimethoxy-chalkon... 

Photolysis of 1,5-diphenyl-1,4-pentadiene is another example of a reaction that takes this... 

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. 

The photochemistry of l,l,5,5-tetraphenyl-3,3-dimethyl-l,4 pentadiene (1) has been studied in detail by Zimmerman and Mariano.<7) Photolysis of compound (1) gave 1,1-diphenyl-2,2-dimethyl-3-(2,2-diphenylvinyl) cyclopropane ... 

The second example is an intermolecular crystal-state reaction. Cross-conjugated 1,5-disubstituted 1,4-dien-3-ones in solution undergo both cis-trans photoisomerization and photodimerization, yielding complex mixtures of products, including die all-trans-substituted cyclobutane 2 in the case of 1,5-diphenyl-1,4-pentadien-3-one. In contrast, dienones such as 3a in whose crystals adjacent molecules lie parallel and strongly overlapped react in the solid to give 3b as the sole photoproduct. This isomerically pure tricyclic diketone results, formally, from an eight-center dimerization. It is not formed in the reaction in solution, and could be prepared by other methods only with considerable difficulty (4). 

An example of the formation of a cyclic product, containing only one sulfur atom, is the reaction of Sx anions with activated double bonds of 1,5 -diphenyl-1,4-pentadiene-3-one yielding in a substituted oxotetrahydrothiopy-ran (Scheme 62) [253]. 

C17H15NO 1,5-diphenyl-l,4-pentadien-3-one oxime Extraction-photometric Cu 61... 

Die mit Palladium-Komplexen wie Bis-[l,5-diphenyl-3-oxo-l,4-pentadien]- und Bis-[1,2-bis-(diphenyl-phosphano)-ethan]-pa ladium(0)2 katalysierte Addition von Allylestern an Imine aus Glycin bzw. Alanin-estem sowie Benzophenon bzw. (4-Chlor)Benzaldehyd kann zur Synthese von Derivaten hoherer und auch funktionalisierter, y, -ungesattigter a-Ami-no-carbonsauren verwendet werden3,4. Im einfachsten fuhrt dies zu solchen der 2-Amino-4-pentensaure. 

When C3 of the 1,4-pentadiene is disubstituted as in 69, the rearrangement is stereospecific at carbons 1 and 5. For example, m-1,1 -diphenyl-3,3-dimethyl-1,4-hexadiene (73) rearranges to 74, in which the side chain is cis, but trans-, -diphenyl-3,3-dimethyl-1,4-hexadiene (75) rearranges to 76, in which the side... 

Cyclobuten-Bildung findet auch bei zahlreichen substituierten 1,3-Buta-dienen statt (z.B. bei Isopren (92,277), 2,3-Dimethylbutadien-(l,3) (92, 277), trans-l,3-Pentadien (277), l-Cyclohexylbutadien-(l,3) (92), Sorbin-alkohol (92) und 2,3-Diphenyl-butadien (322)). Besonders erwahnt sei das 4-Methyl-l,3-pentadien (Formel 60), das bei der UV-Bestrahlung nicht 3,3-Dimethylcyclobuten-(l) (Formel 59), sondem 1,3-Dimethyl-cyclobuten-(l) (Formel 62) (92,126) liefert. 

One example53) of these will suffice. Thus, the photochemical reactions interconverting 1, l-dicarbomethoxy-3,3,5,5-tetraphenyl-1,4-pentadiene, 1,1,2,2-tetraphenyl-3-(2, 2 -dicarbomethoxyvinyl)cyclopropane, and 1,1 -dicarbomethoxy-2,2-diphenyl-3-(2, 2 -diphenylvinyl)cyclopropane are of interest in several ways. The singlet processes provide an example typifying the treatment of many of the cases referenced above. 

Diphenyl-4//-tellurin-4-yKdene)-l,3-pentadien-l-yl]-2,6-diphenyltelluriiriuin TctrafluoroborateA... 

Three unique di-diene have been utilized by Meek (9, 10) in the preparation of Diels-Alder copolymers. Reaction of 1,8-diphenyl-octatetraene with ftts-maleimides in refluxing chloroform for several days affords high yields of polymers with softening temperatures well over 300°, but low intrinsic viscosities. The copolymerization of 1,5-di(9-anthryl)-l,4-pentadiene-3-one and anthralazine with fo s-maleimides employs the diene nature of anthracene to obtain polymers with... 

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