Double nucleophilic N-alkylation of α-oxime-esters with Grignard reagents

Double nucleophilic N-alkylation of α-oxime-esters, affording N,N-dialkyl-α-amino acids is herein described. Grignard reagents accomplished double N-alkylations via umpolung and various N,N-dialkylated α-amino acids were successfully synthesized in 15 min. Both electron-withdrawing sulfonyl groups and electron-donating silyl and methyl groups on oximes were available. Alkylmagnesium species and (E)-configuration of α-oxime-ester were essential to this cascade reaction.