C. Easton
1994
Citations
0
Influential Citations
33
Citations
Journal
Tetrahedron
Abstract
Abstract Side-chain bromination of N -phthaloyl-( S )-phenylalanine and tyrosine derivatives, followed by treatment of the product bromides with silver nitrate in aqueous acetone, affords the corresponding (2 S ,3 R )-β-hydroxy-α-amino acids, enantiospecifically and diastereoselectively. The diastereoselectivity depends on the carboxyl protecting group. tert -Butyl esters display greater stereoselectivity than the corresponding methyl esters, presumably as a result of a steric effect, while N-tert -butylamides react diastereospecifically due to a combination of steric and electronic effects.