Enantiodifferentiation of multifunctional tertiary alcohols by NMR spectroscopy with a Whelk-O type chiral solvating agent

A Whelk-O type chiral solvating agent (CSA) allows NMR enantioresolution of multifunctional tertiary alcohols. Crystallographic analysis of the CSA revealed two conformers, which can be expected to coexist in solution. One conformation affords a chiral cleft that can engage a single enantiomer in simultaneous hydrogen bonding, π–π stacking, and CH/π interactions. This chiral recognition process yields nonequivalent NMR signals for the enantiomers of eighteen substrates even when substoichiometric amounts of the CSA are used.

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