Ir-Catalyzed Reverse Prenylation of 3-Substituted Ind les: Total Synthesis of (+)-Aszonalenin and (-)-Brevicompanine B

The selective reverse prenylation of 3-substituted-1H-indoles at C3 is described. The iridium-catalyzed reaction proceeds with high branched to linear selectivity (>20:1) for a variety of indoles. In addition, a diastereoselective reverse prenylation of tryptophan methyl ester is disclosed, and its synthetic utility is demonstrated in the synthesis of (+)-aszonalenin and (-)-brevicompanine B.