Novel C.sub.3-C.sub.19 alkyl- and aryl-thiotrifluoroacetates are provided which have the structure ##STR00001## wherein Q is C.sub.9-C.sub.19 alkyl or aryl, and are useful protecting agents for the amino or hydroxy functional groups of amines, amino acids or primary or secondary alcohols or amino alcohols to enable formation of amide bonds in peptides or proteins which are useful as screening agents, pharmaceuticals and cosmetics.A process for preparing C.sub.3-C.sub.19 alkyl- and aryl-thiotrifluoroacetates is also provided wherein a C.sub.3-C.sub.19 alkylthiol or arylthiol is treated with trifluoroacetic anhydride (TFAA) in the presence of organic base such as pyridine, a solvent such as dichloromethane (DCM) and dimethylaminopyridine (DMAP) as a catalyst to form the desired C.sub.3-C.sub.19 alkyl- or aryl-thiotrifluoroacetate.In addition, a process for protecting a primary or secondary amino group or a primary or secondary hydroxyl group or an amino alcohol with a trifluoroacetyl protecting group is provided wherein a primary or secondary amine, amino acid, a primary or secondary alcohol or an amino alcohol is treated with a C.sub.3 to C.sub.19 alkyl- or aryl-thiotrifluoroacetate in basic aqueous solution.