A reinvestigation of the α-alkylation of 4-monosubstituted 2-phenyloxazol-5(4H)-ones ('azlactones'): A general entry into highly functionalized α,α-disubstituted α-amino acids

Article abstract of DOI:10.1002/hlca.19940770520

Novel, more reliable and general reaction conditions for the α-alkylation of 4-monosubstituted 2-phenyloxazol-5(4H)-ones (= 4-monosubstituted 2-phenyl-azlactones) rac-2 to 4,4-disubstituted 2-phenyloxazol-5(4H)-ones rac-1 were found. Thus, a whole range of highly functionalized rac-1 were prepared in medium-to-good overall yields (40-90%). Azlactones rac-1 are ideal precursors for the synthesis of optically pure α,α-disubstituted (R)- and (S)-α-amino acids.