Decrypting Transition States by Light: Photoisomerization as a Mechanistic Tool in Bronsted Acid Catalysis.

ABSTRACT: Despite the wide applicability of enantioselective Brønsted acid catalysis, experimental insight into transition states is very rare, and most of the mechanistic knowledge is gained by theoretical calculations. Here, we present an alternative approach (decrypting transition state by light = DTS-hν), which enables the decryption of the transition states involved in chiral phosphoric acids catalyzed addition of nucleophiles to imines. Photoisomerization of double bonds is employed as a mechanistic tool. For this class of reactions four pathways (Type I Z, Type I E, Type II Z, Type II E) are possible, leading to different enantiomers depending on the imine configuration (E- or Z-imine) and on the nucleophilic attack site (top or bottom). We demonstrated that the imine double bond can be isome

SUBMITTER: Renzi P 

PROVIDER: S-EPMC5456416 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature