The synthesis of bromo and iodo trifunctionalised tribenzosilatranes

In this report we present a direct synthesis of bromo 8 and iodo 9 trisubstituted tribenzosilatranes. Commercially available o-anisidine 1 was transformed into the triarylamine 3 in a two-step sequence, which was halogenated to furnish the tribromo 4 or the triiodo 5 substituted triamines, respectively. Subsequent deprotection of the methyl ethers furnished the novel tripod ligands 6 and 7. A transilylation reaction in the last step led to the synthesis of the desired para-halogenated tribenzosilatranes 8 and 9.