Radical-Mediated Approaches for the Synthesis of Thiolactones

In this review we discuss the diverse synthetic approaches and methodologies which have been utilized for the preparation of small and medium ring thiolactones via radical-mediated processes. We provide a brief overview of the major current applications and uses of thiolactones in disparate fields of study and outline a selection of representative methods which have been employed for the preparation of compounds containing this structural motif, with a concise consideration of the conditions employed, the key intermediates formed and the mechanism of the transformations, where pertinent. Reaction classification has been broadly divided into two distinct classes: those in which the key bond forming step is an intermolecular radical process, and those in which it is an intramolecular process (radical cyclization). Both of these reaction classes may be further subdivided into processes that proceed via a carbon-centered (C-centered) radical, and those that proceed through a thiyl/sulfur-centered (S-centered) radical.