NMR Enantiodifferentiation of thiiranium cations by chiral hexacoordinated phosphate anions

The interaction of racemic thiiranium cations and some chiral TRISPHAT anions is reported. Racemic tert-butyl substituted thiiranium ions were chosen for their greater stability with respect to less hindered thiiranium ions. Anions L-BINPHAT and D-TRISPHAT were tested. The use of L- BINPHAT anion allowed a complete separation of all the proton NMR signals of trans-di-tert-butylthiiranium ion and of trans-phenyl-tert- butylthiiranium ion, whereas D-TRISPHAT anions cause the splitting of the ring protons signals only. This is the first report on the NMR enantio- differentiation of chiral thiiranium cations.