Bi(OTf)3—a mild catalyst for the synthesis of difficult to obtain C-alkyl substituted glycolurils

We have employed Bi(OTf)3 (5 mol %) a catalyst not previously used in the synthesis of urea condensation products from α-dicarbonyl compounds, as a mild method for the synthesis of difficult to obtain glycolurils. There are limited synthetic examples of C-alkylated substituted glycolurils and even fewer carrying functionality on the alkyl substituent. We have successfully synthesised some challenging examples of glycolurils with functionality, which include norbornyl-based structures. The milder reaction conditions enables the isolation of defined intermediate diols and ureas in good yields, and glycolurils are possible, where they would not normally be available under conventional acid catalyzed conditions.