ε-Viniferin

ε-Viniferin (CAS 62218-08-0, C₂₈H₂₂O₆, MW 454.47 g/mol) is the 8–10′ oxidative dimer of resveratrol, first isolated from Vitis vinifera by Langcake and Pryce in 1977 (Experientia, 33, 151–152). The 8–10′ connectivity generates a 2,3-diaryl-2,3-dihydrobenzofuran core. Because this dihydrobenzofuran motif recurs throughout higher-order resveratrol oligomers, ε-viniferin functions as a biosynthetic hub: trimers (α-viniferin, gnetin H, miyabenol C) and tetramers (vitisin A, vitisin B) are assembled by convergent coupling of ε-viniferin with resveratrol or with other dimers rather than by stepwise addition of monomers (Keylor, Matsuura & Stephenson, Chem. Rev., 2015, 115, 8976–9027). Natural sources produce both enantiomers: (+)-ε-viniferin [7a(S), 8a(S)] in Vitaceae; (−)-ε-viniferin [7a(R), 8a(R)] in Dipterocarpaceae, Cyperaceae, and most other families (Kurihara et al., Tetrahedron Lett., 1990, 31, 6527–6530).