The synthesis of a chiral receptor molecule containing three carbohydrate residues within a 20-crown-6 constitution

The rationale behind designing and the approach to synthesising chiral crown ethers incorporating three trigonally-disposed carbohydrate residues is presented as a prelude to attaining chiral discrimination in the complexation of ($\text{R}$)- and ($\text{S}$)-α-phenylethylammonium perchlorate.     

The syntheses and complexing properties of oxo-12-crown-3 and oxo-18-crown-5

Derivatives of 12-crown-4 and 18-crown-6 in which one of the ethereal oxygens is replaced by a CO group have been synthesised and their complexing abilities towards both metal and organic cations have been assessed. Variable temperature ¹H decoupled ¹³C n.m.r. spectroscopy reveals the presence of anisometric species in solution when a $\text{1}$:1 complex is formed between oxo-18-crown-5 and (S)-PhCHMeNH₃⁺ClO₄.