A study of hydroboration of alkenes and alkynes with pinacolborane catalyzed by transition metals

Pinacolborane (PBH) is an excellent stoichiometric hydroboration reagent for alkenes and alkynes in the presence of catalytic amounts of transition metals. While Wilkinson's catalyst causes isomerization of internal alkenes, Rh(CO)(PPh3)2Cl gives the internal alkyl pinacolboronates in excellent regioselectivity. Rhodium and also nickel are extremely effective catalysts for the hydroboration of alkynes with PBH.