Abstract
The total synthesis of (±)-methyldecinine, the methyl ether of decinine, was described. The Ullmann reaction of 6-bromoveratraldehyde (IV) with the ester (V) gave the biphenyl (VI) along with the dimeric dialdehyde (VII) and the fluorenones (VIII and IX). The Mannich condensation of isopelletierine with VI afforded stereoselectively the transquinolizidin-2-one (XI), which, on treatment with the Henbest catalyst, furnished the axial alcohol (XII) together with the equatorial alcohol (XIII). Each of the alcohols was shown to be a mixture of two atropisomers from the dynamic nuclear magnetic resonance spectra. Hydrolysis of XII and lactonization of the resulting hydroxy-acid (XIV) provided (±)-methyldecinine (II) in an excellent yield.
