A strong hydride donating, acid stable and reusable 1,4-dihydropyridine for selective aldimine and aldehyde reductions.

A 1,4-dihydropyridine derivative, lacking carbonyl groups and containing bulky aryl substituents, was synthesized and found to have a high hydride donating ability, acid resistance and reusability. Thermodynamic parameters for electron and hydride transfer in the redox system comprising the 1,4-dihydropyridine and its corresponding pyridinium ion were determined. In addition, studies showed that the 1,4-dihydropyridine with steric hindrance can be used to promote efficient, boron trifluoride catalyzed selective reduction reactions of aldimines and aldehydes under mild conditions.