N-Heterocyclic carbene catalyzed asymmetric hydration: direct synthesis of alpha-protio and alpha-deuterio alpha-chloro and alpha-fluoro carboxylic acids.

: Asymmetric hydration of alpha,alpha-dichloro aldehydes and alpha-halo enals via a NHC-catalyzed redox process to yield enantioenriched alpha-chloro and alpha-fluoro carboxylic acids is described herein. The developed reaction allows for installation of an alpha-deuterium to give rise to enantioenriched alpha-deutero alpha-halo acids using D(2)O as the deuteron source.