Total Synthesis of the Dimeric Cephalotaxus Alkaloid (−)-Cephalancetine C

Cephalancetine C, a prototype of the dimeric Cephalotaxus alkaloids, was first synthesized in the laboratory via a convergent two-segment approach. Key steps included an aldol reaction and a stereospecific 5-exo-trig aza-Michael addition. This strategy was developed after an unsuccessful attempt to pursue a biomimetic pathway in which a Polonovski-type reaction of 7 unexpectedly produced conjugated cyclic enamine 8.