SmI₂(H₂O)_n Reduction of Electron Rich Enamines by Proton-Coupled Electron Transfer.

ABSTRACT: Samarium diiodide in the presence of water and THF (SmI₂(H₂O)_n) has in recent years become a versatile and useful reagent, mainly for reducing carbonyl-type substrates. This work reports the reduction of several enamines by SmI₂(H₂O)_n. Mechanistic experiments implicate a concerted proton-coupled electron transfer (PCET) pathway, based on various pieces of evidence against initial outer-sphere electron transfer, proton transfer, or substrate coordination. A thermochemical analysis indicates that the C-H bond formed in the rate-determining step has a bond dissociation free energy (BDFE) of ∼32 kcal mol^-1. The O-H BDFE of the samarium aquo ion is estimated to be 26 kcal mol^-1, which is among the weakest kn

SUBMITTER: Kolmar SS 

PROVIDER: S-EPMC5812026 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature