An asymmetric synthesis of L-[3-13C]phenylalanine and L-[3- 13C]tyrosine from [13C]carbon monoxide

Article abstract of DOI:10.1016/S0040-4020(98)00995-8

L-[3-¹³C]Phenylalanine and L-[3-¹³C]tyrosine were synthesized. [α- ¹³C]Benzyl bromides were prepared from [¹³C]carbon monoxide via the palladium-catalyzed carboalkoxylation of aryl halides. The asymmetric carbon corresponding to the 2-position in phenylalanine was introduced by the diastereoselective alkylation of Dellaria's oxazinone with [α-¹³C]benzyl bromides. Finally, ethanolysis, deprotection, hydrogenolysis and acid hydrolysis of the resulting alkylated oxazinones gave L-[3- ¹³C]phenylalanine and L-[3-¹³C]tyrosine in high optical purity.