Functional crown ethers with chlorocyclophosphazene sub-units as anion activators and promoters of highly regioselective reactions
Abstract
The effect of the metal ion on the regiochemical outcome has been revealed in the nucleophilic substitution reactions of diphosphaza[16]crown-6 with a series of alkali metal p-nitrophenoxides in low polarity ia a host–guest interaction with the alkali metal p-nitrophenoxide, both the activation of the anion and the regiocontrol of the chlorine substitution in the phosphazenic ring (‘P-crown’
s. ‘P-non-crown’ substitution). As a consequence of this supramolecular control, it is possible to switch the reaction pattern toward electronically and sterically
unfavored regioselective substitution at the position geminal to the