Neighbouring group effects promote substitution reactions over elimination and provide a stereocontrolled route to chloramphenicol
作者:Christopher J. Easton、Craig A. Hutton、Martin C. Merrett、Edward R.T. Tiekink
DOI:10.1016/0040-4020(96)00307-9
日期:1996.5
In reactions of β-brominated valine and p-nitrophenylalanine derivatives to give β-hydroxy amino acid derivatives the carboxyl group, when protected as an amide, exerts a neighbouringgroup effect to facilitate the substitution process, and reduce competing eliminationreactions. As a consequence of the effect, the (2R,3R)- and (2R,3S)-stereoisomers of 3-bromo-N-tert-butyl-Nα-phthaloyl-p-nitrophenylalaninamide