Stereochemical Determination of Five-Membered Cyclic Ether Acetogenins Using a Spin-Spin Coupling Constant Approach and DFT Calculations
Adrián Gutiérrez-Cepeda,
Antonio Hernández Daranas,
José J. Fernández,
Manuel Norte,
María L. Souto
Affiliations
Adrián Gutiérrez-Cepeda
University Institute of Bio-Organic Chemistry "Antonio González", Center for Biomedical Research of the Canary Islands (CIBICAN), University of La Laguna, Astrofísico Francisco Sánchez 2, La Laguna 38206, Tenerife, Spain
Antonio Hernández Daranas
University Institute of Bio-Organic Chemistry "Antonio González", Center for Biomedical Research of the Canary Islands (CIBICAN), University of La Laguna, Astrofísico Francisco Sánchez 2, La Laguna 38206, Tenerife, Spain
José J. Fernández
University Institute of Bio-Organic Chemistry "Antonio González", Center for Biomedical Research of the Canary Islands (CIBICAN), University of La Laguna, Astrofísico Francisco Sánchez 2, La Laguna 38206, Tenerife, Spain
Manuel Norte
University Institute of Bio-Organic Chemistry "Antonio González", Center for Biomedical Research of the Canary Islands (CIBICAN), University of La Laguna, Astrofísico Francisco Sánchez 2, La Laguna 38206, Tenerife, Spain
María L. Souto
University Institute of Bio-Organic Chemistry "Antonio González", Center for Biomedical Research of the Canary Islands (CIBICAN), University of La Laguna, Astrofísico Francisco Sánchez 2, La Laguna 38206, Tenerife, Spain
Five-membered rings are of particular interest, due to their presence in some of the most common molecules in chemistry and biology. Despite their apparent simplicity, the structural resolution of these rings is complex, due to their inherent conformational flexibility. Here, we describe an application of a recently reported simple and efficient NMR protocol based on the measurement of spin-spin coupling constants to achieve the challenging relative configurations of five new halogenated C15 tetrahydrofuranyl-acetogenins, marilzafurollenes A–D (1–4) and 12-acetoxy-marilzafurenyne (5), isolated from the red alga, Laurencia marilzae. Although DFT chemical shift calculations were used to connect remote stereocenters, the NMR-based approach seems advantageous over computational techniques in this context, as the presence of halogens may interfere with reliable calculations.
