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

Abstract

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 iJ/DP4 statistical analysis and further confirmed by measuring two anisotropic properties: carbon residual chemical shift anisotropies (13C-RCSAs) and one-bond 1H-13C residual dipolar couplings (1DCH-RDCs). The absolute configuration of 1b was deduced by ECD/OR/TD-DFT methods and established as 3R,7S,11R.

Keywords

• <i>Sargassum muticum</i>
• meroditerpene
• coupling constants
• <i>J</i>-DP4
• ¹³C-RCSA
• RDC