Studies on the Mechanism-of-Action of Prekinamycin a Member of the Diazoparaquinone Family of Natural Products: Evidence for both sp2 Radical and Orthoquinonemethide Intermediates

摘要

The putative reductive activation chemistry of the diazoparaquinone antibiotics was modeled with Bu3Sn–H and prekinamycin dimethyl ether along with prekinamycin itself. Reaction in various combinations of aromatic solvents, with and without the nucleophile benzylmercaptan present, led to isolation of both radical trapping arene adducts and nucleophilic capture benzyl thioether products. Based upon these product distribution studies, the intermediacy of first, a cyclopentenyl radical, and next, an orthoquinonemethide electrophile, is postulated.