Aza-annulation strategies in alkaloid total synthesis

This review highlights the synthesis of nitrogen-containing natural products via aza-annulation. Strategic, tactical, and methodological perspectives are discussed, including recent developments such as metal- or organocatalyzed reactions, oxidative or reductive cyclizations, biomimetic processes, cascade reactions, and cycloadditions. Such key steps are presented in the context of the total syntheses of tropinone, batzelladine, lyconadin, FR901483, strychnofoline, discorhabdin, necatarone, aspidophytine, dibromophakellstatin, anachelin, the acridones, alkaloid GB 13, cephalotaxine, strychnine, setoclavine, porantherine, vallesamine, nitraramine, cylindricine, the daphniphyllines, symbiomime, alstonerine, tangutorine and flustramine.