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 alkynyl-amide and NBS-mediated oxidative Friedel-Crafts cyclization of the resulting 2-ketopiperazine were utilized as key reactions.