The manzamine alkaloid keramamine C contains a unique azacycloundecene subunit, which is constructed by ring‐closing metathesis exploiting the intrinsic H‐bond‐induced conformational fixation of an amide bond. Taking advantage of this particular effect, the alkaloid could be prepared from readily available precursors in only five synthetic steps, where important further insight into the otherwise challenging ring‐closing metathesis of 11‐membered lactams was gained.
Ganzmann et al. (Sat,) studied this question.