147620-06-2Relevant academic research and scientific papers
Visible light mediated reductions of ethers, amines and sulfides
Monos, Timothy M.,Magallanes, Gabriel,Sebren, Leanne J.,Stephenson, Corey R.J.
, p. 240 - 248 (2016/07/21)
Visible light-mediated photoredox catalysis enables the chemoselective reduction of activated carbon–heteroatom bonds as a function of reduction potential. The expansion of the scope of C–X bond reductions towards less activated motifs, such as ethers, amines and sulfides, is important to both organic synthesis and macromolecular degradation method development. In the present report, exploration of photoredox catalysis in alcoholic solvents mediated a decrease in the super-stoichiometric use of iPr2NEt and HCO2H in the reduction of α-keto ethers, amines and sulfides. Additionally, in the absence of fragmentation, [Formula presented] bond formation was afforded, suggesting an intermediate ketyl radicals are present in these transformations.
Enolate Structures Contributing to the Transition State for Nucleophilic Substitution on α-Substituted Carbonyl Compounds
Yousaf, T. I.,Lewis, E. S.
, p. 6137 - 6142 (2007/10/02)
The high SN2 reactivity of α-halocarbonyl compounds is explained by the lowering of the intrinsic barrier by a major contribution of enolate structure to the transition state.This theoretical conclusion is now shown experimentally.The evidence is as follows: (1) Change in structure of a leaving arenesulfonate ion does not change the rates of attack of benzenesulfonate ion by nearly as much as it changes the equilibrium constants.A charge on the transferring phenacyl group of -0.48 is deduced. (2) The ρ value (-3.9) for attack of substituted thiophenoxides on phenacyl bromide is much more negative than that for attack on methyl iodide (-1.8). (3) A related ρ value is found for reaction of 2,4,6-trimethylphenacyl bromide with thiophenoxides (-2.2), showing a lesser, but still large sensitivity to nucleophile structure where addition to the carbonyl is sterically forbidden.The enolate structure leaves the attacking or leaving nucleophiles with a single electron each instead of the unshared pairs.Thus, the enolate structure is emphesized if the leaving group and the nucleophile readily lose an electron.
