Connection of Isolated Stereoclusters by Combining 13 C-RCSA, RDC, and J -Based Configurational Analyses and Structural Revision of a Tetraprenyltoluquinol Chromane Meroterpenoid from Sargassum muticum .

The seaweed Sargassum muticum , collected on the southern coast of Galicia, yielded a tetraprenyltoluquinol chromane meroditerpene compound known as 1b , whose structure is revised. The relative configuration of 1b was determined by J -based configurational methodology combined with an i J /DP4 statistical analysis and further confirmed by measuring two anisotropic properties: carbon residual chemical shift anisotropies ( 13 C-RCSAs) and one-bond 1 H- 13 C residual dipolar couplings ( 1 D CH -RDCs). The absolute configuration of 1b was deduced by ECD/OR/TD-DFT methods and established as 3R , 7S , 11R .