The effectiveness of cyclooctadiene and norbornadiene precatalysts of the type [Rh (DuPHOS)(diolefin)] BF4 in catalytic asymmetric hydrogenation of various prochiral olefins has been examined. In some of the systems studied, the NBD complex gave rise to the catalytically active species more rapidly than the corresponding COD complex, as expected. However, as catalyst loadings were reduced to levels more conducive to economic ...
