Fischer Indole Synthesis

Abstract

This chapter focuses on recent applications in drug development, materials discovery, and natural-product synthesis. The mechanism of the Fischer indole synthesis has been extensively studied, and the accepted mechanism is shown in the chapter. The so-called abnormal Fischer indolization has been studied by Ishii and Murakani and their coworkers, and the interrupted Fischer indolization has been evaluated theoretically by Houk, Garg, and colleagues. Several key pieces of the mechanistic puzzle that encompass the Fischer indolization mechanism are depicted in the chapter. The chapter then encounters additional examples of two powerful Grandberg syntheses in the Applications section, namely, Borsche–Drechsel carbazole synthesis and Bucherer carbazole synthesis. It presents naturally occurring indoles and related unnatural analogues that have been synthesized via Fischer indolization. The chapter finally discusses applications to the synthesis of indoles.