30078-89-8Relevant articles and documents
Chromium-Catalyzed Linear-Selective Alkylation of Aldehydes with Alkenes
Hirao, Yuki,Kanai, Motomu,Katayama, Yuri,Mitsunuma, Harunobu
supporting information, (2020/11/18)
We developed a chromium-catalyzed, photochemical, and linear-selective alkylation of aldehydes with alkylzirconium species generated in situ from a wide range of alkenes and Schwartz's reagent. Photochemical homolysis of the C-Zr bond afforded alkyl radicals, which were then trapped by a chromium complex catalyst to generate the alkylchromium(III) species for polar addition to aldehydes. The reaction proceeded with high functional group tolerance at ambient temperature under visible-light irradiation.
Photoenzymatic Catalysis Enables Radical-Mediated Ketone Reduction in Ene-Reductases
Sandoval, Braddock A.,Kurtoic, Sarah I.,Chung, Megan M.,Biegasiewicz, Kyle F.,Hyster, Todd K.
supporting information, p. 8714 - 8718 (2019/05/28)
Flavin-dependent ene-reductases (EREDs) are known to stereoselectively reduce activated alkenes, but are inactive toward carbonyls. Demonstrated here is that in the presence of photoredox catalysts, these enzymes will reduce aromatic ketones. Mechanistic experiments suggest this reaction proceeds through ketyl radical formation, a reaction pathway that is distinct from the native hydride-transfer mechanism. Furthermore, this reactivity is accessible without modification of either the enzyme or cofactors, allowing both native and non-natural mechanisms to occur simultaneously. Based on control experiments, we hypothesize that binding to the enzyme active site attenuates the reduction potential of the substrate, enabling single-electron reduction. This reactivity highlights opportunities to access new catalytic manifolds by merging photoredox catalysis with biocatalysis.
Regioselective Sulfonylvinylation of the Unactivated C(sp3)-H Bond via a C-Centered Radical-Mediated Hydrogen Atom Transfer (HAT) Process
Yang, Shan,Wu, Xinxin,Wu, Shuo,Zhu, Chen
supporting information, p. 4837 - 4841 (2019/06/24)
Given the similarity of multiple sp3 C-H bonds in electronic properties and bond dissociation energy (BDE), regioselective sp3 C-H bond functionalization remains a paramount challenge. Here, we report a C-centered radical-mediated approach for site-specific sulfonylvinylation of the C(sp3)-H bond via the hydrogen atom transfer (HAT) process. The reaction features mild conditions, broad substrate scope, and high regioselectivity and stereoselectivity, manifesting the nontrivial synthetic potential.