The propargyloxycarbonyl group readily introduced to both amino and hydroxy groups by using propargyl chloroformate is stable to neat TFA but is readily cleaved at ambient temperature by treatment with Co-2(CO)(8) and TFA in CH2Cl2 via formation of an alkyne-Co complex. The propargyl ester similarly serves as a good protecting group for carboxy functions. (C) 1999 Elsevier Science Ltd. All rights reserved.