Aporphine Alkaloid Synthesis and Diversification via Direct Arylation

Palladium‐catalyzed direct arylation of aryl chlorides, bromides and iodides has been applied to the preparation of new aporphine analogues including C2‐substituted aporphines by reaction with benzodioxole, pyridine N ‐oxide and pyrazine N ‐oxide. Successful application of direct arylation in these diversification reactions highlights its utility not only in convergent, but also in divergent synthesis. We also describe enantioselective syntheses of ( R )‐nornuciferine and ( R )‐nuciferine employing a catalytic asymmetric transfer hydrogenation in high yield and excellent enantiomeric excess. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)