Additive-free chemoselective acylation of amines and thiols

Amines with different stereoelectronic nature were efficiently acylated at room temperature using acetic anhydride in the presence of no solvent or additive. Various thiols also react equally well under the same conditions. Chemoselective protection of amines in the presence of thiols, alcohols, and phenols and of thiols in the presence of alcohols, and phenols were achieved using competitive experiments.