Palladium-catalyzed enantioselective diboration of prochiral allenes.

Pd-catalyzed diboration of prochiral allenes occurs exclusively at the internal position and is remarkably accelerated in the presence of Lewis basic ligand structures. On the basis of preliminary observations, a chiral ligand was employed, and the enantiomeric excess of a variety of diboration products was found to be in the range of 86-92% ee. The chiral diboron reaction products should be useful in organic synthesis, and preliminary experiments suggest that they may participate in allylation reactions with a high level of chirality transfer.