Application of vinyl tris(trimethylsilyl)germanes in Pd-catalyzed couplings.

The oxidative treatment of vinyltris(trimethylsilyl)germanes with hydrogen peroxide (NaOH/H 2 O/THF) or tert-butyl peroxide (KH/THF) generates reactive germanol or german-oxane species that undergo Pd-catalyzed cross-couplings with aryl and alkenyl halides and aryl triflates in the presence of Pd(PPh 3 ) 4 . Vinylgermanes having either a conjugated or isolated double bond serve as versatile trans-metalation reagents. The E-germanes undergo coupling with retention of stereochemistry under aqueous and anhydrous conditions, while coupling of Z-germanes occurs with less stereoselectivity to produce a mixture of E/Z products.