A New Class of Ferrocene-Based l,2-Bis(phosphanes) Possessing only Planar Chirality

Chiral 1,2-bis(phosphanes) 13, devoid of individual chiral centers, have been prepared in three steps from chiral sulfoxide 10. Their corresponding rhodium complexes were used as catalysts for asymmetric hydrogenation, giving high ee values (⩽ 95%) in the reduction of itaconic acid or its ester. A cationic rhodium complex involving coordination of two molecules of 13b and one molecule of oxygen has been isolated and its crystal structure established.