On the racemization of chiral imidazolines.

Racemization of chiral imidazolines with base has been studied for the first time following an unexpected finding in the synthesis of chiral imidazoline ligands. Amine bases do not cause racemization. Strong inorganic bases can induce racemization, yet this occurs only when the nitrogen is unsubstituted, in agreement with a symmetry-allowed thermal disrotatory ring opening and closure from a diazapentadienyl anion.

Scope and mechanistic insights into the use of tetradecyl(trihexyl)phosphonium bistriflimide: a remarkably selective ionic liquid solvent for substitution reactions.

A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro over nitroso products and elimination side products.