Palladium-Catalyzed 1,2-Addition of Organic Halides and Terminal Alkynes to 7-Oxabenzonorbornadiene: An Efficient Route to Polyaromatic Hydrocarbons

A three-component coupling reaction of organic halides with oxabicyclic alkenes and terminal alkynes was catalyzed by a palladium complex and a phase-transfer agent in the presence of aqueous NaOH. The reaction gave a series of 5,6-disubstituated 7-oxabenzonorbornene derivatives in good yields. The disubstituted products from oxabenzonorbornadiene can be readily converted into polyaromatic hydrocarbons by a Lewis acid mediated deoxyaromatization reaction. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).