Zn(ClO4)2·6H2O as a Powerful Catalyst for a Practical Acylation of Alcohols with Acid Anhydrides

• Published in: European journal of organic chemistry Vol. 2003; no. 23; pp. 4611 - 4617
• Main Authors: Bartoli, Giuseppe, Bosco, Marcella, Dalpozzo, Renato, Marcantoni, Enrico, Massaccesi, Massimo, Sambri, Letizia
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.12.2003; WILEY‐VCH Verlag
• Subjects: Acylations; Alcohols; Anhydrides; Esters; Zinc perchlorate
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.200300458

A new protocol for the acylation of alcohols with anhydrides in the presence of Zn(ClO4)2·6H2O as the catalyst is reported. The activity of Zn(ClO4)2·6H2O has been proven to be superior to that exerted by dry Mg(ClO4)2 and by metal triflates. Its efficiency allows reactions between poorly reactive substrates, such as sterically hindered tertiary alcohols and aromatic anhydrides. All of the reactions were carried out at a 1:1.05 alcohol/anhydride ratio. These conditions are extremely convenient from a practical and economic point of view, since they avoid wasting reagents and allow a simple workup procedure. The catalytic action of Zn(ClO4)2·6H2O is so specific for the activation of the anhydrides, that acid‐sensitive functionalities and the stereochemical configuration of the starting materials remain unaltered in the esterification process. In all cases, the acylated products are quantitatively obtained in pure form. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)