A Lewis Base Catalysis Approach for the Photoredox Activation of Boronic Acids and Esters

Abstract

We report herein the use of a dual catalytic system comprising of a Lewis base catalyst such as quinuclidin-3-ol or 4- dimethylaminopyridine combined with a photoredox catalyst to generate carbon radicals from either boronic acids or esters. This system enabled a wide range of alkyl boronic esters and aryl or alkyl boronic acids to react via radical addition with electron-deficient olefins to efficiently form C–C coupled products in a redox neutral fashion. The Lewis base catalyst was shown to form a redox-active complex with either boronic esters or the trimeric form of the boronic acids (boroxines) in solution.We are grateful to Novartis Pharma AG (F.L.), the Erasmus Scholarship Scheme (L.G. and S.J.), and the EPSRC (S.V.L., Grants EP/K009494/1, EP/K039520/1, and EP/M004120/1) for financial support. U.K.S. and D.S. are thankful to the University of Leuven for postdoctoral funding and the FWO for a visiting postdoctoral scholarship (U.K.S.) at the University of Cambridge. E.V.V.d.E. would like to thank the Ministry of Education and Science of the Russian Federation for financial support (agreement number 02.a03.0008). We thank Dr. Berthold Schenkel and Dr. Gottfried Sedelmeier for insightful discussions. We thank Merck Rahway USA for the generous gift of the PC(1) photoredox catalyst

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