Highly enantioselective allylation of aromatic alpha-keto phosphonates catalyzed by chiral N,N'-dioxide-indium(III) complexes

The ramipril derivative N,N'-dioxide 3g-indium(III) complex was found to be an efficient catalyst for the allylation of the aromatic alpha-keto phosphonates. The corresponding a-hydroxy phosphonates were obtained with high yields (up to 98%) and high enantioselectivities (up to 91% ee). A bifunctional catalyst system was described with an N-oxide as Lewis base activating tetraallyltin and indium as Lewis acid activating aromatic cc-keto phosphonates. A possible catalytic cycle has been proposed to explain the mechanism of the reaction.