Regioselective Direct C-4 Functionalization of Indole: Total Syntheses of (-)-Agroclavine and (-)-Elymoclavine.

An efficient rhodium-catalyzed method for direct C-H functionalization at the C4 position of unprotected indoles has been developed. The utility of this method is demonstrated by the concise total syntheses of agroclavine and elymoclavine in a divergent manner. These syntheses feature a Pd-catalyzed asymmetric allylic alkylation reaction to assemble the triyclic indole moiety, and a ring-closing metathesis reaction to form the D ring.