ASYMMETRIC ELECTROPHILIC AMINATION OF CHIRAL PHOSPHORUS-STABILIZED ANIONS

The asymmetric electrophilic amination of phosphorus-stabilized anions derived from chiral oxazaphosphorinanes and diazaphospholidines is described. Trisyl azide is the reagent of choice for the amination process. The reaction is shown to be dependent on auxiliary structure, nature of the P-alkyl substituent and choice of amination procedure. Using the oxazaphosphorinanes 1a and cis-1e a high level of asymmetric induction can be achieved. Scalemic cis-1e provides the alpha-aminophosphonic acid 13 with 92% e.e. in the (S) antipode. The implications for anion conformation and effect of auxiliary structure on stereoselectivity are discussed.