On the rearrangement of -aryl--Boc-phosphoramidates to -Boc-protected -aminoarylphosphonates.

ABSTRACT

Various arylamines were converted in two steps to -Boc--arylphosphoramidates. LiTMP and LDA induced directed -metalation at temperatures from -78 to 0 °C. The ensuing [1,3]-migration of the phosphorus atom with its substituents from the nitrogen to the -carbanionic carbon atom gave -Boc-protected -aminoarylphosphonates. The nature of the substituent of 3-substituted phenylphosphoramidates strongly influenced the regioselectivity of phosphonate formation. A crossover experiment with a deuterated phosphoramidate proved the intramolecular course of the rearrangement. Three representative -Boc--aminoarylphosphonates were deprotected to access the corresponding -aminoarylphosphonic acids.