Site Selective Csp3–Csp / Csp3–Csp2 Cross Coupling Reactions Using Frustrated Lewis Pairs: data

The donor-acceptor ability of frustrated Lewis pairs (FLPs) has led to widespread applications in organic synthesis. Single electron transfer from donor Lewis base to acceptor Lewis acid can generate the frustrated radical pair (FRP) depending on the substrate and energy required (thermal or photochemical) to promote an FLP into an FRP system. Herein, we report the C_sp3–C_sp cross coupling reaction of aryl esters with terminal alkynes using the B(C₆F₅)₃/Mes₃P FLP. Significantly, when the 1-ethynyl-4-vinylbenzene substrate was employed, exclusive formation of C_sp3–C_sp cross coupled products were observed. However, when 1-ethynyl-2-vinylbenzene was employed, solvent dependent site selective C_sp3–C_sp or C_sp3–C_sp2 cross coupling resulted. The nature of these reaction pathways and their selectivity has been investigated by extensive electron paramagnetic resonance (EPR) studies, kinetic studies, and density functional theory (DFT) calculations to elucidate both the mechanism of these coupling reactions as well as to explain the solvent dependent site selectivity. Data includes experimental procedures and characterisation data.

Research results based upon these data are published at https://doi.org/10.1021/jacs.1c01622