Liste
Précédente Suivante
Publication 134
- Enantioselective systheses of α-amino acids from 10-sulfonamido-isobornyl esters and di-t-butyl azodicarboxylate
Oppolzer, W.; Moretti, R.
Tetrahedron 1988, 44, 5541-5552
Successive treatment of chiral esters 7 with LDA/Me3SiCl and di-t-butyl azodicarboxylate/TiCl4 and Ti(OiPr)4 gave N,N-di-t-butoxycarbonylhydrazinoesters 11 which on deacylation, hydrogenolysis, transesterification and acidic hydrolysis furnished (2S)-α -amino acid hydrochlorides 13 in good overall yields, high enantiomeric purity and with efficient recovery of the alcohol auxiliary 4. Experimental evidence for the configuration and conformation of the intermediate O-silyl ketene acetals 1 is provided.