Alkylsilicates are key building blocks for the cross-coupling reactions of sp3-sp2 and sp3-sp3 carbon centers that were developed by Professor Gary A. Molander at the University of Pennsylvania in 2016.
Cross-coupling of sp3-sp2 carbon centers is particularly important for drug discovery as it has been reported that compounds with lower sp3 fractions have higher rates of attrition in drug development. A few examples of sp3-sp2 cross-couplings reactions between alkylsilicates and p-cyanobromobenzene with Ir/Ni dual catalysis were first reported in 2015 by the Fensterbank group (ACIE, 2015, 54, 11414), but a general synthetic method was not available until 2016. The Molander group at the University of Pennsylvania demonstrated that alkylsilicates undergo sp3-sp2 cross-coupling reactions with a broad range of aryl and alkenyl compounds via a photoredox dual catalysis of ruthenium and nickel. The reaction conditions are mild and suitable for both small-scale lab syntheses and large-scale commercial production. Alkylsilicates are stable solids that can be stored for long periods of time at ambient temperature.