Structure and synthesis of phlobatannins related to the (4β,6:4α,8)- bis-fisetinidol-catechin profisetinidin triflavanoid

Article abstract of DOI:10.1016/0031-9422(96)00114-8

Several members of the class of natural phlobatannins, representing the products of stereoselective pyran rearrangement of the 2,3-trans-3,4-trans- and 3,4-cis-flavan-3-ol units in the (4β,6:4α,8)-bis-fisetinidol-catechin triflavanoid have been characterized. These comprise a functionalized hexahydro-dipyrano-[2,3-f:2',3'h]-chromene, two fisetinidol-(4α, 10)- tetrahydropyrano[2,3-f]chromenes and a pair of fisetinidol-(4α,10)- tetrahydropyrano[3,2-g]chromenes. The proposed structures of these novel compounds were confirmed by synthesis via base-catalysed conversion of the 4- O(E)-methyl ether of their presumed triflavanoid biogenetic precursor.