172. Non-destructive Cleavage of N-Acylsultams Under Neutral Conditions: Preparation of Enantiomerically, Pure Fmoc-Protected α-Amino Acids
     Oppolzer, W.; Lienard, P.
     Helv. Chim. Acta 1992, 75, 2572-2582

Heating diastereoisomerically pure N-acylsultams 3 or 4 with allyl alcohol/Ti(OR)₄ efficiently yields sultams 1 or 2 and allyl esters 5. Esters5 are hydrolyzed under nonbasic conditions in the presence of Wilkinson's catalyst to give enantiomerically and diastereoisomerically pure carboxylic acids 7. A series of [(fluoren-9-yl)methoxy]-carbonyl-(Fmoc)-protected amino acids 14 were thus prepared from N-[N'-(Fmoc)amino]acylsultams 12.

DOI : 10.1002/hlca.19920750812 

archive ouverte unige:90947