Stereocontrolled synthesis of β-hydroxyphenylalanine and β-hydroxytyrosine derivatives
                                
                                    
                                        作者:Christopher J. Easton、Craig A. Hutton、Peter D. Roselt、Edward R.T. Tiekink                                    
                                    
                                        DOI:10.1016/s0040-4020(01)85256-x
                                    
                                    
                                        日期:1994.1
                                    
                                    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 (2S,3R)-beta-hydroxy-alpha-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.