Concise Synthesis of the CDE Ring System of Tetrahydroisoquinoline Alkaloids Using Carbophilic Lewis Acid-Catalyzed Hydroamidation and Oxidative Friedel−Crafts Cyclization

A concise synthesis of the CDE ring system of the tetrahydroisoquinoline antitumor alkaloids such as saframycins, renieramycins, and ecteinascidins has been developed. Both Au(I)-catalyzed intramolecular hydroamidation of alkynylamide and NBS-mediated oxidative Friedel−Crafts cyclization of the resulting 2-ketopiperazine were utilized as key reactions.