the region 220~240 nm (Figure ), characteristic for -substituted flavan-3-ol moieties, confirming the absolute configuration of the spiro center III-C-3 as being S. The absolute configurations of the C-4 centers in both units I and II were thus assigned as R-configured. I-C-2 was S-configured based on the inherent 2,4-cis configuration in A-type PACs. A NOESY correlation between I-H-3 and II-H-6 indicated H-3 and H-4 in the C-ring to be trans, thus I-C-3 was R-configured. The upfield shift of II-C-2 (C 78.7) suggested a 2,4-trans-configuration in the F-ring based on the -gauche effect. Unit II was, therefore, epicatechin (2R, 3R), which was confirmed by the NOESY correlations between II-H-2/III-H-2 and III-H-6. NOESY correlations from III-H-2 to IV-H-3, IV-H-2, and IV-H-6 assigned III-C-2 as R-configured, which determined the terminal unit IV as catechin (2R, 3S). In conclusion, the structure of 2, was assigned unambiguously as shown and named as pinuspirotetrin.