The development of a ‘safety‐catch’ arylgermane for biaryl synthesis by palladium‐catalysed germyl‐stille cross‐coupling

Abstract

AbstractThe Pd(0) catalysed cross‐coupling of arylgermanes with aryl bromides is shown to require at least two labile heteroatom ligands on the Ge centre to allow efficient nucleophilic activation by fluoride. Dichloroarylgermanes 7a and 7b are shown to cross‐couple to a series of aryl bromides with moderate efficiency using activation by KF in DMF. Bis(2‐naphthylmethyl)arylgermane 18b is identified as a ‘safety‐catch’ precursor to this type of cross‐coupling substrate. The 2‐naphthylmethyl substituents can be removed via photolytic oxidation in the presence of Cu(BF4)2 and the resulting species, although not characterized, participates in cross‐coupling using activation by TBAF in DMF. Copyright © 2007 John Wiley & Sons, Ltd.