Stereodivergent Synthesis of Alkaloid (±)-223A and (±)-6- epi-223A via Rh-Catalyzed Hydroformylation Double Cyclization

J Org Chem. 2024 Apr 5;89(7):5091-5097. doi: 10.1021/acs.joc.3c02366. Epub 2024 Mar 8.

Abstract

A stereodivergent approach toward total syntheses of Dendrobatid alkaloids 223A and 6-epi-223A is described. The approach features a concise construction of an indolizidine skeleton by Rh-catalyzed domino hydroformylation double cyclization and sequential stereocontrolled transformations such as reductive alkylation or anti-selective α-alkylation of the 5-oxoindolizidine. These stereoselective reactions afford the desired stereochemistry in the targets.