Neoteric Solvents for Exploratory Catalysis: Hydrophosphination Catalysis with CHEM21 Solvents

The development of catalytic hydrophosphination has placed little emphasis on solvent effects, and most exploratory studies continue to be in toxic or environmentally harmful solvents. A comparative analysis of hydrophosphination catalysis using the three major categories of substrates, styrene, Michael acceptors, and unactivated alkenes, has been undertaken to assess a transition to green solvent alternatives. The compound selected, Cu(acac)2, has been identified as a highly active and perhaps most general precatalyst for hydrophosphination, which is enabled by photochemical conditions. Eight solvents were investigated from categories outlined in the CHEM21 guide, and seven were highly effective for most reactions. These results demonstrate a straightforward path to improving the sustainability of future studies in this and related catalytic reactions through bioavailable solvents, as well as highlighting potential pitfalls in reactions involving phosphine substrates.