Tandem Annulations of Propargylic Alcohols to Indole Derivatives

Abstract Indole derivatives are important heterocycles in organic synthesis for serving as privileged building blocks for functional material and as key components in a lot of bioactive compounds. Propargylic alcohols, bearing alkynyl and hydroxyl functional groups, have emerged as promising feedstock materials for the construction of carbo‐ and heterocycles. Especially, in the last decade, the Lewis or Brønsted acid catalysed tandem annulations of propargylic alcohols to build structurally diverse indole derivatives have been well‐investigated. In this review, we summarize two main synthetic strategies toward indole derivatives via the cascade reactions of propargylic alcohols: indole‐ring formation involved tandem reactions and the direct function‐alization of indole skeletons. We hope this review would help to develop new and more efficient protocols for the synthesis of indole‐included N ‐heterocycles. magnified image