Synthesis of chiral α-substituted N-[((2S)-2-hydroxy-2-phenyl)-ethyl]-2-phenylglycine derivatives by diastereocontrolled alkylation of (6R)-2,3,5,6-tetrahydro-3,6-diaryl-N-[(2'R)-(2'-methyl)phenyl-methyl]-4H-1,4 -oxazin-2-ones

Article abstract of DOI:10.1016/S0040-4020(97)10235-6

The synthesis of α-substituted N-[((2S)-2-hydroxy-2-phenyl)-ethyl]-2-phenylglycine derivatives is reported, The key step of the sequence is the highly diastereoselective alkylation of (6R)-2,3,5,6-tetrahydro-3,6-diaryl-N-[(2'R)-(2'-methyl)phenylmethyl]-4H-1,4 -oxazin-2-ones after deprotonation with t-BuOK. Opening of the resulting oxazinone with ethanolic KOH, followed by hydrogenolysis of the corresponding N-[(2R)-(2-methyl)phenylmethyl] compound to furnish the expected 2-phenylglycine derivative, is also described.