Highly Efficient Synthesis of Substituted Benzenes in the Presence of B(HSO4)3 as a New and Reusable Catalyst Under Solvent-Free Conditions

A highly efficient and simple procedure for the synthesis of substituted benzenes is described. A broad range of ketones (alkyl-aryl ketones and cyclic ketones) were condensed via a cyclotrimerization reaction in the presence of catalytic amounts of boron sulfonic acid [B(HSO4)(3)], a new, highly efficient, and reusable catalyst, under solvent-free conditions. All reactions completed in short times without formation of any by-products. The catalyst was recovered and reused successfully for 15cycles of the reaction. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.