Synthesis of Indole Substituted Twistenediones from a 2‑Quinonyl Boronic Acid

Indole substituted twistane-like derivatives resulted in a reaction between 3,5-dimethyl-2-quinonyl boronic acid and 2-alkenyl indoles. Their MCPBA oxidation gave 6/6/9 caged systems. Boronic acid acts as a temporal promoter allowing a site-selective conjugate addition of the heteroaromatic system to the methyl substituted C-3 quinone carbon, giving an intermediate diene which is regioselectively trapped by intramolecular [4 + 2] cycloaddition.