Total Syntheses of Arylindolizidine Alkaloids (+)-Ipalbidine and (+)-Antofine

This paper presents the first application of two recently developed reactions to natural product synthesis. The first method involves a 6-endo-trig cyclization to prepare a versatile chiral enaminone building block. The second is a direct C−H arylation reaction. As a showcase for the utility of these methods, (+)-antofine and (+)-ipalbidine were synthesized in only 8 steps and 24−26% overall yields.