SEARCH Articles Figures Tables Base-catalyzed rearrangements Of pyrans Oligomeric proanthocyanidin Oligomeric proanthocyanidins Oligomeric rings Oligomerization base-catalyzed Oligomerization, catalyzed Proanthocyanidin Proanthocyanidins Proanthocyanidins rearrangement Pyrans rearrangement Rearrangements of Ring Ring rearrangements