Thallium(III) Chloride: A Mild and Efficient Catalyst for Acylation of Alcohols, Phenols and Thiols, and for Geminal Diacylation of Aldehydes under Solvent-Free Conditions

Thallium(III) chloride is a simple and efficient catalyst for acylation of alcohols, phenols and thiols. It is also very effective for geminal diacylation of aldehydes. The acylation reaction using acetic anhydride proceeds in excellent yield in the presence of catalytic amounts of thallium(III) chloride (1 mol%) at room temperature within relatively short reaction times (<20 min). Structurally diverse alcohols, phenols, thiols and aldehydes undergo acylation under solvent-free conditions.