Stereoselektive Synthese von optisch aktivem Vincamin

Abstract
Vincamine (13) was prepared from the aldehyde 8 in 5 steps using methyl dimethyl‐phosphono‐methoxy‐acetate as a synthon for the pyruvic ester residue. A method to convert apovincamine (12) into vincamine (13) has hen worked out. Optically active 8 was synthesized from ethyl‐malonaldehydic acid ethyl ester in 9 steps including optical revolution of the acid intermediate 3 by means of salt formation with L‐(+)‐pseudoephedrine. The two diastereomeric salts were distinguishable by NMR. in carbontetrachloride.