Diethoxyphosphoryl as a protecting-activating group in the synthesis of polyazacyclophanes

The fully diethoxyphosphoryl(Dep)-protected polyamines 1b-3b were prepared from the corresponding polyamines with 'diethyl phosphite' (= diethyl phosphonate) and CCl4 in a solid base/organic liquid two-phase system in the presence of Bu4NBr as phase-transfer catalyst. Subsequent phase-transfer-catalyzed alkylation of phosphoramidates 1b-3b with bis(chloromethyl)arenes 5-8 in the presence of Bu4N(HSO4) followed by deprotection gave good yields of polyazacyclophanes 9a-16a