Regioselective Formation of Enediynes via Intramolecular Trapping of Allylic Cations

Enediynes are a novel class of naturally occurring antitumor antibiotics capable of causing DNA strand cleavage by hydrogen atom abstraction from the deoxyribose backbone. During the past decade, numerous synthetic methods have been developed to synthesize the naturally occurring and the "designed" enediynes for biomedical studies. Recently, we have succeeded in assembling the cis-enediynes 2 by a novel and high-yielding allylic rearrangement under mild reaction conditions (Eq 1).^1-3 This methodology has been used to synthesize a 10-membered ring enediyne³ which exhibits DNA cleavage activity.