Synthesis of the Tetracyclic Spiro-naphthoquinone Chartspiroton

Org Lett. 2024 Apr 19;26(15):3065-3068. doi: 10.1021/acs.orglett.4c00695. Epub 2024 Apr 1.

Abstract

Chartspiroton is a recently discovered naphthoquinone natural product that features a spiro-fused benzofuran lactone. We report its first synthesis via an 11-step linear sequence. The sterically hindered tetra-ortho-substituted biaryl subunit was installed by base-induced ring expansion of a readily available 1,3-indandione. This step also liberated the fully substituted naphthalene core unit at the same time. The unique spiro-fused benzofuran lactone of the natural product was constructed via late-stage oxidation of an advanced naphthoquinone.