2D‐NMR ConformationaL Studies of ChiraL Functionalized Ferrocenylphosphine Ligands for the Gold(I)‐Catalyzed Aldol Reaction

The conformations in solution of six selected chiral 1,1′‐bis (diphenylphosphino)ferrocenyl ligands bearing functionalized side chains, the diastercoisomers 4 and 5 and 6–9, have been elucidated by 2D‐NMR methods (COSY, TOCSY, NOESY, and 1H,31P and 1H,13C correlations). The possible relationship between the preferred conformation and the stereoselectivity observed in the gold(I)‐catalyzed asymmetric aldol condensation in the presence of these ligands is discussed.