Stereochemical consequences of the intramolecular hydrogen bond in 1′-acetyl-1-α-hydroxyethyl- and 1,1′-bis(α-hydroxyethyl)ferrocenes

1′-Acetyl-1-α-hydroxyethyl- and 1,1′-bis(α-hydroxyethyl)ferrocenes and the carbocations derived from them have been characterized by electronic, infrared and NMR spectroscopy. The existence of intramolecular hydrogen bonds between the interannular substituents in the various species examined has been established. The restricted rotation caused by such interaction leads to preferential formation of pairs of enantiomers.