The phase-transfer catalytic alkylation of N, N-dialkylmalonamic tert-butyl esters in the presence of 1 mol% of (S, S)-3, 4, 5-trifluorophenyl-NAS bromide afforded highly enantioselective (S)-mono-α-alkylated products (up to 96% ee), which could be readily converted into versatile chiral building blocks without loss of chirality.
