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Updated: Mar 22, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Palladium-Catalyzed Oxidative Carbocyclization-Borylation of Enallenes to Cyclobutenes
Youai Qiu1, Bin Yang1, Can Zhu2
1Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden.
Abstract:
A highly efficient palladium-catalyzed oxidative borylation of enallenes was developed for the selective formation of cyclobutene derivatives and fully-substituted alkenylboron compounds. Cyclobutenes are formed as the exclusive products in MeOH in the presence of H2 O and Et3 N, whereas the use of AcOH leads to alkenylboron compounds. Both reactions showed a broad substrate scope and good tolerance for various functional groups, including carboxylic acid ester, free hydroxy, imide, and alkyl groups. Furthermore, transformations of the borylated products were conducted to show their potential applications.
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