Studies in Cephalotaxus Alkaloids. Stereospecific Total Synthesis of Homoharringtonine

Article abstract of DOI:10.1021/jo00174a031

The alkaloid ester homoharringtonine (2) was synthesized stereospecifically via the Reformatsky reaction of methyl α-bromoacetate with cephalotaxyl pyruvate (16) obtained by esterification of cephalotaxine with acid chloride derived from 15.The preparations of 2 and its unsaturated derivative 13 are described in detail.Possible explanations of the steric requirements in the esterification of cephalotaxine and of the steric outcome of the Reformatsky reaction leading to 2 and 13 are advanced.