2-Hydroxy-5,5-dialkyl-δ-valerolactone derivatives as chiral dopants for practical ferroelectric liquid crystals

2-Hydroxy-5,5-dialkyl-δ-valerolactone derivatives have shown interesting properties as a chiral dopant for ferroelectric liquid crystals. In small amounts these compounds induce high magnitudes of spontaneous polarization and long helical pitches in the chiral nematic phase (N*). Alkyl chains attached at the C-5 position play an important role in these properties. Here we discuss the stereochemistry and ferroelectric properties of these lactones and compare them with those of 2-hydroxy-5-alkyl-δ-valerolactone derivatives reported previously. The ring structure of 5,5-dialkyl-δ-valerolactone is found to be a rigid 'pseudo-chair' conformation by *H NMR studies.