Fig. 4: Synthesis of α-amino acids.

a The scope of the amine substrates. b The scope of the benzoquinone and Wittig reagent substrates. c The scope of the alkyne substrates. ^aCH₃CN as solvent. Ph phenyl, Et ethyl, p-Tolyl 4-methyl-phenyl, Bn benzyl, i-Pr isopropyl, t-Bu tert-butyl.