The diastereoselective synthesis of unsymmetrically 2,2"-disubstituted biferrocenesdiphosphine

Two sets of unsymmetrically 2,2"-disubstituted biferrocenes derivatives was diastereoselective synthesized by Negishi coupling reaction. The coupling reaction of (R)-1- (N,N-dimethylamino)ethylferrocene with racemic 2-bromo-iodoferrocene led to two diastereomeric products. Further selective transformations on these coupling products allowed them transformed intocorresponding2,2"-disubstituted biferrocenes diphosphines as potential asymmetric ligands and catalysts.