Alkaloids bearing the indole moiety constitute one of the most important groups of natural products, mainly due to their remarkable biological activity. Usually, these heterocyclic compounds are substituted in the very reactive two and three positions. In 2010, raputindoles A-D were isolated from the Amazonian plant Raputia simulans Kallunki (Rutaceae), which was collected in Peru. In 2011, a Brazilian research group reported a new analogue for this class of compounds. These bisindoles possess a cyclopentyl unit fused to the benzene ring of one of the indoles and constitute a novel class of indole alkaloids. This project aims to develop a route to the asymmetric synthesis of raputindole D, using hypervalent iodine reagents in the key transformations, including the iodine(III)-mediated ring contraction reaction developed in our research group and an alkynylation using an iodonium salt. The proposed synthesis is convergent and can be easily adapted to other raputindoles.
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