An evaluation of phosphine and carbene adducts of phosphite- and phosphinite-based palladacycles in the coupling of alkyl bromides with aryl boronic acids

A range of palladacyclic catalysts and their phosphine and carbene adducts were tested in the Suzuki coupling of an alkyl bromide with phenylboronic acid and showed modest activity in some cases. Unlike with aryl halide substrates it appears that there is no particular benefit in the use of palladacycles as the palladium source. Initial data indicate that the rate determining step is not the oxidative addition of the alkyl halide substrate, but rather lies later in the catalytic cycle.