Catalytic Asymmetric Aziridination with Arylborate Catalysts Derived from VAPOL and VANOL Ligands

The asymmetric induction is essentially identical for a range of substrates when the the VAPOL and VANOL (see picture; but not 1,1′-binaphth-2-ol (BINOL)) ligands were employed in asymmetric aziridinations catalyzed by triphenylborate (90–98 % ee). The synthetic utility of these catalysts is illustrated in a synthesis of L-3,4-dihydroxyphenylalanine (L-DOPA).