Dimerization of resveratrol

Cichewicz RH, Konzi SA, Hamann MT. 2000. Dimerization of resveratrol by the grapevine pathogen Botrytis cinerea. J Nat Prod 63 29-33. 

Pezet R, Gindro K, Viret O, Spring J-L. 2004. Glycosylation and oxidative dimerization of resveratrol are respectively associated to sensitivity and resistance of grapevine cultivars to downy mildew. Physiol Molec Plant Pathol 65 297-303. 

Dimerization of resveratrol by the grapevine pathogen, Botrytis cinerea, R.M. 

An efficient asymmetric synthesis of substituted methyl 2-aryl-dihydrobenzo[h]furan-3-carlx)xylate was achieved by a rhodium-catalyzed C-H bond activation route in an excellent yield, and the generated product was an intermediate applicable to the total synthesis of (+)-lithospermic acid <0 A13496>. A similar type of framework existing in ( )-E-viniferin was m e through a biomimetic transformation by a T1(N03)3-mediated oxidative dimerization of resveratrol <05T10285>. 

Fig. (2). Depiction of a proposed biosynthetic scheme for the dimerization of resveratrol (1) to (+)-e-viniferin (11a)...

Piver B, Berthou F, Dreano Y, Eucas D (2003) Differential inhibition of human cytochrome P450 enzymes by epsilon-viniferin, the dimer of resveratrol comparison with resveratrol and polyphenols from alcoholized beverages. Life Sci 73 1199-1213... 

Numerous stilbenes such as e-viniferin (Landrault et al. 2002) and 5-viniferin, two resveratrol dehydrodimers (Vitrac et al. 2005), the resveratrol dimer pallidol (Vitrac et al. 2001), a-viniferin, a trimer of resveratrol (Pryce and Langcake 1977)... 

Two glycosides of resveratrol polymer, gnemonoside B (29) and K (30) have cis olefinic bonds in their aglycones, The aglycone moieties of gnemonoside H (31) and F (32) are dimer and trimer of resveratrol, and each of them is connected with 3 glucoses, respectively [19,20]. 

Recently, two glycosides of stilbene dimer named compound 1 (33) and compound 2 (34) were obtained from an aqueous extract of the roots of Polygonum cuspidatum. Among them, 34 was a new type of resveratrol dimer possessing a four-membered ring [21]. 

Red sandalwood Pterocarpus santalinus has attracted interest as a colourant and contains the colourless components, pterostilbene (34), pterocarpin (35) and homopterocarpin (36) the occurrence of which (ref. 101)and the chemistry (ref. 102) have been reviewed. The nature of the possible involvement of these compounds in the development of colour in sandalwood is not known although quinone and quinone dimer structures seem highly probable. Pterostilbene is the dimethyl ether of resveratrole, a natural widely-occurring phenolic component of many plants including grapes, mulberries and peanuts. The anticancer properties (ref. 103) and beneficial effect on coronary heart disease of this have been intensively studied recently (ref 104). ... 

A rapid analysis of resveratrol, trans-E-viniferin, and trans-5-viniferin from downy mildew-infected grapevine leaves by liquid chromatography-atmospheric pressure photoionization mass spectrometry was performed [168]. The characterization of unknown stilbene derivatives such as six resveratrol dimers, two dimethylated... 

It was shown that treating 5-[2-(4-hydroxyphenyl)vinyl]benzene-l,3-diol (resveratrol) with an equimolar amount of silver(I) acetate in dry MeOH at 50 °C for 1 h, followed by chromatographic purification with a short silica gel column, allowed the isolation of its ( )-dehydrodimer, 5-[5-[2-(3,5-dihydroxyphenyl)vinyl]-2-(4-hydroxyphenyl)-2,3-dihydrobenzofuran-3-yl]benzene-l,3-diol, as a racemic mixture in high yield. The present method was applicable to the oxidative dimerization of 4-hydroxystilbenes such as trows-styrylphenol and 5-[6-hydroxy-2-(4-hydroxyphenyl)-4-[2-(4-hydroxyphenyl)-vinyl]-2,3-dihydrobenzofuran-3-yl]benzene-l,3-diol (epsilon-viniferin) leading to the corresponding 2-(4-hydroxyphenyl)-2,3-dihydrobenzofurans possessing various types of biological activities. 

The group of resveratrol oligomers comprises the largest number of oligostilbenes and is characterized by the polymerization of two to eight resveratrols. About 180 constituents of this group covering dimer to octamers have been reported, which is produced by diverse polymeric styles. 

On the other hand, the group of Yang has disclosed a convenient Tf O-catalyzed FC alkylation protocol to synthesize the dibenzo[a,treatment with a catalytic amount (lOmol-%) of Tf O in toluene at 100°C provided ( )-ampelopsin B (119) in 41% yield. The reaction is thought to be initiated by reaction of TfjO with trace water to release a proton that coordinates with the alkene to form a carbocation intermediate. 

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