Jump to main content
Jump to site search

Issue 38, 2016
Previous Article Next Article

Proton-coupled electron transfer in the reduction of carbonyls using SmI2–H2O: implications for the reductive coupling of acyl-type ketyl radicals with SmI2–H2O

Author affiliations

Abstract

Samarium diiodide–water (SmI2–H2O) reagents have emerged as some of the most practical systems enabling reduction and reductive cyclizations of ketyl radicals. Recently, this reaction manifold has been extended to acyl-type radicals generated from cyclic polar carboxylic acid derivatives. However, the relationship between the fundamental electron- and proton-transfer steps in the generation of ketyl-type radicals with SmI2–H2O remains unclear. An intriguing scenario involves an initial proton-coupled electron transfer (PCET) mechanism from SmI2–H2O to the carbonyl group. Herein, we calculate with high accuracy bond dissociation free energies (BDFE) for the O–H bond in ketyl radicals in 14 cyclic and acyclic ketone, ester, imide and amide substrates and in anthracene relevant to reductions with SmI2–H2O and quantitatively assess the feasibility of concerted PCET in the reduction of carbonyl groups using SmI2–H2O. Reduction potentials of all substrates have been calculated. The data argue against concerted PCET from SmI2–H2O to carbonyl substrates.

Graphical abstract: Proton-coupled electron transfer in the reduction of carbonyls using SmI2–H2O: implications for the reductive coupling of acyl-type ketyl radicals with SmI2–H2O

Back to tab navigation

Supplementary files

Publication details

The article was received on 29 Jul 2016, accepted on 01 Sep 2016 and first published on 12 Sep 2016


Article type: Paper
DOI: 10.1039/C6OB01621A
Org. Biomol. Chem., 2016,14, 9151-9157

  •   Request permissions

    Proton-coupled electron transfer in the reduction of carbonyls using SmI2–H2O: implications for the reductive coupling of acyl-type ketyl radicals with SmI2–H2O

    S. Shi, R. Szostak and M. Szostak, Org. Biomol. Chem., 2016, 14, 9151
    DOI: 10.1039/C6OB01621A

Search articles by author

Spotlight

Advertisements