Extensive high‐resolution reverse 2D NMR analysis for the structural elucidation of procyanidin oligomers

Abstract
The structures of the procyanidin dimers catechin‐(4α–8)‐catechin and catechin‐(4α–6)‐catechin were proved by spectroscopic means. To distinguish between the two possible interflavanoid linkages, it is necessary to assign all the quaternary aromatic carbon signals. How these assignments can be made through two‐dimensional NMR spectroscopy is described.