All four stereoisomers of the highly constrained aromatic α-amino acid β-isopropyl-2′, 6′- dimethyltyrosine have been asymmetrically synthesized on a large scale. A catalytic asymmetric Michael addition of an organocuprate to a chiral α, β-unsaturated acyloxazolidinone and subsequent direct or indirect stereoselective electrophilic azidation of the α-position of the resulting product was followed by hydrolysis, hydrogenation and ...
