Connection of Isolated Stereoclusters by Combining <sup>13</sup>C-RCSA, RDC, and <i>J</i>-Based Configurational Analyses and Structural Revision of a Tetraprenyltoluquinol Chromane Meroterpenoid from <i>Sargassum muticum</i>
Juan Carlos C. Fuentes-Monteverde,
Nilamoni Nath,
Abel M. Forero,
Elena M. Balboa,
Armando Navarro-Vázquez,
Christian Griesinger,
Carlos Jiménez,
Jaime Rodríguez
Affiliations
Juan Carlos C. Fuentes-Monteverde
Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain
Nilamoni Nath
Department of Chemistry, Gauhati University, Gopinath Bardoloi Nagar, Guwahati 781014, India
Abel M. Forero
Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain
Elena M. Balboa
Department of Chemical Engineering, Faculty of Science, Campus Ourense, University of Vigo, As Lagoas s/n, 32004 Ourense, Spain
Armando Navarro-Vázquez
Departamento de Química Fundamental, CCEN, Universidade Federal de Pernambuco, Cidade Universitária, Recife 50740-550, Brazil
Christian Griesinger
NMR Based Structural Biology, MPI for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
Carlos Jiménez
Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain
Jaime Rodríguez
Departamento de Química e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña, 15071 A Coruña, Spain
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.
