Spotlights on Recent JACS Publications.

发表于：Journal of the American Chemical Society · 年份：2019 · DOI：10.1021/jacs.9b05416 · 研究领域：Medicine

Structural editing in organic chemistry often involves the positional isomerization of alkene substrates. This positional transposition is often thermodynamically controlled, with lesssubstituted alkenes undergoing isomerization to more-substituted ones. However, the opposite mode of transposition is not common. Furthermore, even though some literature exists on isomerizing internal alkenes to terminal ones, such methods are often stepwise and require stoichiometric amounts of the reagents involved. Therefore, a catalytic approach to positionally transposing more-substituted alkenes into less-substituted ones would bring in an innovative strategy in the positional editing of organic compounds. Kuo Zhao and Robert Knowles now describe a beautifully executed positional isomerization of internal alkenes to generate terminal products using dual photoredox−chromium catalysis (DOI: 10.1021/jacs.1c11681). First, the authors activate the more stable internal alkene through an excited-state oxidant and involve a Brønsted base to generate an intermediate radical. A chromium catalyst then captures this radical to generate an allylchromium species, which eventually undergoes a protodemetalation. This work is applicable in complex molecule settings and constitutes a significant advancement in contra-thermodynamic positional alkene isomerization, leveraging differences in the oxidation potential of the alkene isomers. Suman Chakrabarty Ph.D.