N-Phosphoryl amino acids were prepared rapidly and in high yield via p
hosphoramidite amine-exchange in the presence of 1H-tetrazole followed
by oxidation with mCPBA. Formation of dibenzyl phosphoramidates incor
porating the representative C-terminal protected amino acids leucine,
phenylalanine, glutamic acid, and proline were demonstrated to be most
successful with dibenzyl N,N-dimethylphosphoramidite although the N,N
-diethyl and N,N-diisopropyl analogs also provided high yields. (C) 19
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