Solid trichlorotitanium(IV) trifluoromethanesulfonate TiCl3(OTf) catalyzed efficient acylation of –OH and –SH: Direct esterification of alcohols with carboxylic acids and transesterification of alcohols with esters under neat conditions

Solid TiCl 3 (OTf) catalyzed acetylation of alcohols, phenols and thiols with acetic anhydride in the absence of organic solvents at room temperature in a short reaction time. Benzoylation of alcohols, phenols and thiols also proceeded at higher temperature (∼80 °C) under solvent-free conditions. Transesterification of alcohols with ethyl acetate and ethyl formate was also carried out efficiently in the presence of this catalyst. Direct esterification of different alcohols with different carboxylic acids also occurred readily in the presence of this catalyst and in the absence of any organic solvents.