NONDESTRUCTIVE CLEAVAGE OF N-ACYLSULTAMS UNDER NEUTRAL CONDITIONS - PREPARATION OF ENANTIOMERICALLY, PURE FMOC-PROTECTED ALPHA-AMINO-ACIDS

Heating diastereoisomerically pure N-acylsultams 3 or 4 with allyl alcohol/Ti(OR)4 efficiently yields sultams 1 or 2 and allyl esters 5. Esters 5 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)methoxyl-carbonyl-(Fmoc)-protected amino acids 14 were thus prepared from N-[N'-(Fmoc)amino]acylsultams 12.