Abstract
In this chapter, advances in the applications of manganese(III)-based oxidative free radical cyclizations over the past 25 years are reviewed including the use of various copper(II) salts to oxidize the cyclic radical intermediate. Following a mechanistic introduction, cyclizations are reviewed and organized by the type of ring formed (cycloalkanone, cycloalkane, lactone, and lactam) and by the number (1–4) of rings formed. In addition, new methodological developments are detailed and applications to natural product synthesis are featured.