Stilbene chemistry

Judged by the magnitude of , these eliminations have product-like transition states. With respect to stilbene chemistry the pattern of Fig. 27 is rather general. That is, the relative reactivity of the two stilbenes is often small, e.g. within a factor of two in some (not all) additions of bromine (Buckles et al., 1967), 2,4-dinitrosulfenyl chloride (Slobodkin and Kharasch, 1960) or trichloromethyl (Cadogan and Inward, 1962). 

As described in this chapter, stilbenes synthetic chemistry has been making gradual progress for the past two decades, paving the way for more fundamental uses and applications of stilbenes in research fields of both materials and life sciences. We could not give all details and references to cover this vast area in limited pages. Therefore, readers who want to study stilbenes chemistry further are recommended to consult relevant papers, reviews, and books cited in references. 

Recently, the chiral Pt(0) precatalyst Pt[(R, R)-Me-Duphos](trows-stilbene) (11) has been used to prepare enantiomerically enriched chiral phosphines via hydrophosphination of acrylonitrile, t-butyl acrylate and related substrates. This chemistry is summarized in Scheme 5-13. 

This protocol could be extended to a range of different ,/i-unsaturated carbonyl compounds and either activated or deactivated aryl iodides [22], An application of related Heck chemistry to the synthesis of methylated resveratrol (3,4, 5-trihydroxy-( )-stilbene) is shown in Scheme 6.4 [23]. The phytoalexin resveratrol exhibits a variety of interesting biological and therapeutic properties, among them activity against several human cancer cell lines. Botella and Najera have shown that the trimethyl ether of resveratrol (Scheme 6.4) can be rapidly prepared by microwave-assisted Heck reaction of the appropriate aryl iodide and styrene derivatives, using the same oxime-derived palladacycle as indicated in Scheme 6.3. 

The electrophilic bromination of ethylenic compounds, a reaction familiar to all chemists, is part of the basic knowledge of organic chemistry and is therefore included in every chemical textbook. It is still nowadays presented as a simple two-step, trans-addition involving the famous bromonium ion as the key intermediate. T]nis mechanism was postulated as early as the 1930s by Bartlett and Tarbell (1936) from the kinetics of bromination of trans-stilbene in methanol and by Roberts and Kimball (1937) from stereochemical results on cis- and trans-2-butene bromination. According to their scheme (Scheme 1), bromo-derivatives useful as intermediates in organic synthesis... 

SCHRODER, J., The chalcone/stilbene synthase-type family of condensing enzymes. In Comprehensive Natural Products Chemistry, vol. 1, Polyketides and Other Secondary Metabolites Including Fatty Acids and Their Derivatives (U. Sankawa ed.), Elsevier, Amersterdam, 1999, pp. 749-771. 

Identification by Syntheses of a Product from the Cationic Oligomerisation of Stilbene in Toluene, D.S. Brackman and P.H. Plesch, Chemistry and Industry, 1955, 255. 

H.-O. Hamaguchi and K. Iwata, Physical chemistry of the lowest excited singlet state of trans-stilbene in solution as studied by time-resolved Raman spectroscopy, Bull. Chem. Soc. Jpn. 2002, 75(5), 883. 

Spectroscopic evidence for the transient formation of the trans-stilbene radical cation could be obtained when colloidal TiOj suspended in an acetonitrile solution containing trans-stilbene (a species which should also be exothermically oxidized by a TiO valence band hole) was excited with a laser pulse The observed transient was identical in spectroscopic features and in lifetime with an authentic sample of the stilbene cation radical generated in the same medium via pulse radiolytic techniques. That the surface influences the subsequent chemistry of this species can be seen in the distribution of products observed under steady state illumination, Eq. (4) 2 . ... 

Bimolecular Photochemical Reactions of the Stilbenes By Frederick D. Lewis, Department of Chemistry,... 

Resveratrol is a member of the stilbene family, a group of compounds which consist of two aromatic rings joined by a methylene bridge. 3,4, 5-trihydrox-ystilbene is the IUPAC (International Union of Pure and Applied Chemistry) nomenclature for resveratrol but is also known as 3,4, 5-stilbenetriol, and it has... 

Schroder J (1999) The chalcone/stilbene-synthase family of condensing enzymes. In Sankawa U (ed) Comprehensive natural products chemistry, vol 1. Pergamon, Oxford, pp 749-771... 

Organic Chemistry in Supercritical Fluid Solvents Photoisomerization of trans- Stilbene... 

Yasuda, M., Isami, T., Kubo, J., Mizutani, M., Yamashita, T., and Shima, K. (1992) Regiochemistry on photoamination of stilbene derivatives with ammonia via electron transfer. Journal of Organic Chemistry, 57, 1351—1354. 

Lee, G.A. (1976) Photochemistry of cis-and trons-stilbene oxides. Journal of Organic Chemistry, 41, 2656-2658. 

Boyd, J.D. and Foote, C.S. (1979) Chemistry of singlet oxygen. 32. Unusual products from low-temperature photooxygenation of indenes and trans-stilbene. Journal of the American Chemical Society, 101 (22), 6758-6759. 

The chemistry of 306 differs from that of its seven-membered analogue in that its reaction with rram-stilbene gives reductive coupling product 308 in addition to the stilbene adduct of zirconocene, the sole product of the latter (vide infra). This was attributed to differences in ring strain.116... 

---