Total Synthesis of (+)-Raputindole A: An Iridium-Catalyzed Cyclization Approach

Juliana L L F Regueira; Luiz F Silva Jr; Ronaldo A Pilli

doi:10.1021/acs.orglett.0c01943

Total Synthesis of (+)-Raputindole A: An Iridium-Catalyzed Cyclization Approach

Org Lett. 2020 Aug 21;22(16):6262-6266. doi: 10.1021/acs.orglett.0c01943. Epub 2020 Aug 5.

Authors

Juliana L L F Regueira^{1

2}, Luiz F Silva Jr¹, Ronaldo A Pilli²

Affiliations

¹ Institute of Chemistry, University of São Paulo (USP), 05508-000 São Paulo, São Paulo, Brazil.
² Institute of Chemistry, University of Campinas, 13083-970 Campinas, São Paulo, Brazil.

Abstract

This work describes the total synthesis of raputindole A (1) through a convergent approach that features (1) an iridium-catalyzed cyclization to assemble the tricyclic core of the northern part, (2) enzymatic resolution to secure the preparation of an enantiomerically pure benzylic alcohol intermediate, and (3) the installation of the isobutenyl side chain via methallylation of the corresponding benzylic carbocation and coupling of the northern and southern parts via the Heck reaction. (+)-Raputindole A (1) was prepared in 10 steps (longest linear sequence) in 3.3% overall yield.

Publication types

Research Support, Non-U.S. Gov't