Synthesis of a novel chiral binaphthyl phospholane and its application in the highly enantioselective hydrogenation of enamides

[GRAPHICS] A new chiral phosphine, (R,R)-1,2-bis{(R)-4,5-dihydro-3H-dinaphtho[2,1-c:1' ,2'-e]phosphepino}benzene {abbreviated as (R,R)-binaphane} was prepared on the basis of a practical route from a readily accessible enantiomerically p ure binaphthanol. This ligand possesses both binaphthyl chirality and phosp holane functionality. Excellent enantioselectivities (95-99.6% ee) have bee n observed in hydrogenation of an isomeric mixture of (E)- and (Z)-beta-sub stituted-alpha-arylenamides by using a Rh-binaphane catalyst. These enantio selectivities are the highest reported to date for this transformation.