Alkylammoniotrifluoroborate functionalized polystyrenes: polymeric pre-catalysts for the metal-free borylation of heteroarenes

Abstract

Three polymeric versions of ansa-N,N-dialkylammoniumtrifluoroborate ambiphilic molecules based on the styrene motif (poly(1-NMe₂H⁺-2-BF₃⁻-4-styrene) (P-Me), poly(1-NEt₂H⁺-2-BF₃⁻-4-styrene) (P-Et) and poly(1-piperidinyl-H⁺-2-BF₃⁻-4-styrene) (P-Pip)) were synthesized, characterized and tested as heterogeneous pre-catalysts for the borylation of electron-rich heteroarenes. These heterogeneous versions of previously reported pre-catalysts show similar reactivity patterns and represent the first examples of solid-supported FLP metal-free catalysts for the C–H borylation of heteroarenes.