Single Oxygen-Atom Insertion into PB Bonds: On- and Off-Metal Transformation of a Borylphosphine into a Borylphosphinite

An oxygen atom is selectively inserted into the PB bond of a borylphosphine (L1) by reaction with Me3NO to afford the corresponding borylphosphinite (L2). This transformation can also be effected when L1 is coordinated to rhodium. The ν(CO) values for trans-[RhCl(CO)(L)2] reveal very different electronic properties for coordinated L1 and L2 which translate into the strikingly different performances of the complexes [RhCl(L)(cod)] (L=L1 or L2, cod=1,5-cyclooctadiene) in hydrosilylation and hydroboration catalysis.