Lewis acid–base 1,2-addition reactions: synthesis of pyrylium borates from en-ynoate precursors†
Abstract
Treatment of methyl (Z)-2-alken-4-ynoates with the strong Lewis acid tris(pentafluorophenyl) borane, B(C6F5)3, yield substituted zwitterionic pyrylium borate species via an intramolecular 6-endo-dig cyclisation reaction.
- This article is part of the themed collection: Main Group Transformations