Hydroboration of unsaturated phosphonic esters: Synthesis of boronophosphonates and trisubstituted vinylphosphonates

[GRAPHICS] Hydroboration of vinyl phosphonates with pinacolborane (PBH) proceeds to gi ve phosphonoboronates, 2, Surprisingly, such compounds have not been report ed before, The reaction works well with terminal alkenylphosphonates, Inter nal alkenylphosphonates give complex mixtures, Hydroboration/Suzuki couplin g of alkynylphosphonates, with PBH, in a one-pot procedure gives trisubstit uted vinylphosphonates in good overall yields and provides a new synthesis of these compounds.