Synthesis of (R)-alpha-benzylmethionine: a novel rearrangement during alkylation of the Seebach (R)-methionine oxazolidinone.
Alkylation of the enolate of the Seebach (R)-methionine oxazolidinone with benzyl bromide gave the expected benzylated product in low yield. The major product was a novel amine arising from oxazolidinone cleavage, decarboxylation, alkylation and finally hydrolysis. The rearrangement could be suppressed by using a more reactive electrophile or by using the N-Cbz instead of the N-benzoyl protecting group, and the required (R)-alpha-benzyl-methionine was obtained in 78% yield and in an enantiomeric ratio of 90:10.
Procopiou
Panayiotis A
PA
GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, UK SG1 2NY. pan.a.procopiou@gsk.com
Ahmed
Mahmood
M
Jeulin
Séverine
S
Perciaccante
Rossana
R