39236-18-5Relevant academic research and scientific papers
Synthesis of Each Stereoisomer of Phenylalanine and Evaluation of the Stereochemical Course of the Reaction of (R)-Phenylalanine with (S)-Phenylalanine Ammonia-lyase
Easton, Christopher J.,Hutton, Craig, A.
, p. 3545 - 3548 (2007/10/02)
The four stereoisomers of phenylalanine have been prepared, each as a single enantiomer in ca. 98percent diastereoisomeric excess and with ca. 99percent deuterium incorporation, by side-chain bromination of phenylalanine derivatives, followed by deuteriolysis of each of the diastereoisomeric product bromides with deuterium over 5percent palladium-on-carbon.The latter reactions proceeded with retention of configuration. (2R,3S)-Phenylalanine reacted with (S)-phenylalanine ammonia-lyase to give -trans-cinnamic acid, with 92percent deuterium incorporation, while the (2R,3R)-stereoisomer of the deuterated phenylalanine gave -trans-cinnamic acid with 27percent deuterium incorporation.These results indicate that reaction of (R)-phenylalanine with the enzyme involves mainly loss of the 3-pro-R hydrogen and ammonia, in an antiperiplanar elimination process analogous to that previously reported for (S)-phenylalanine, while a minor pathway for reaction of (R)-phenylalanine is either isomerization to (S)-phenylalanine, before elimination, or synperiplanar elimination.
