*Review* **The Tetrahydrofuran Motif in Polyketide Marine Drugs**

**Laura Fernández-Peña, Carlos Díez-Poza, Paula González-Andrés and Asunción Barbero \***

> Department of Organic Chemistry, Campus Miguel Delibes, University of Valladolid, 47011 Valladolid, Spain; laura.fernandez.pena@uva.es (L.F.-P.); carlos.diez@uva.es (C.D.-P.); paula.gonzalez.andres@alumnos.uva.es (P.G.-A.)

**\*** Correspondence: asuncion.barbero@uva.es

**Abstract:** Oxygen heterocycles are units that are abundant in a grea<sup>t</sup> number of marine natural products. Among them, marine polyketides containing tetrahydrofuran rings have attracted grea<sup>t</sup> attention within the scientific community due to their challenging structures and promising biological activities. An overview of the most important marine tetrahydrofuran polyketides, with a focused discussion on their isolation, structure determination, approaches to their total synthesis, and biological studies is provided.

**Keywords:** marine natural products; oxygen heterocycles; tetrahydrofuran; total synthesis; biological activity
