P-CHLOROTETRAFLUOROPHENYL ESTERS OF N-PROTECTED AMINO-ACIDS

p-Chlorotetrafluorophenyl (Tfc) esters of protected amino acids and pe ptides are more reactive than are the well known pentafluorophenyl (Pf p) esters, Two reagents, p-chlorotetrafluorophenyltrifluoroacetate (Tf c-OTfa) and di-(p-chlorotetrafluorophenyl)carbonate (di-Tfc-carbonate) , can be used for their syntheses, thereby avoiding use of the allergi c dicyclohexylcarbodiimide. This is especially important for bulk prep arations. Many Fmoc- and Boc-amino acid-OTfc esters have been synthesi zed and characterized. The hexadecameric tandem repeat H-(AlaAlaLysPro )(4)-OH was synthesized using di-Tfc-carbonate for the preparation of Tfc-esters. (C) Munksgaard 1994.