Decatungstate-catalyzed radical disulfuration through direct C-H functionalization for the preparation of unsymmetrical disulfides

Abstract

Unsymmetrical disulfides are widely found in the areas of food chemistry, pharmaceutical industry, chemical biology and polymer science. Due the importance of such disulfides in various fields, general methods for the nondirected intermolecular disulfuration of C-H bonds are highly desirable. In this work, the conversion of aliphatic C(sp3)-H bonds and aldehydic C(sp2)-H bonds into the corresponding C-SS bonds with tetrasulfides (RSSSSR) as radical disulfuration reagents is reported. The decatungstate anion ([W10O32]4−) as photocatalyst is used for C-radical generation via intermolecular hydrogen atom transfer in combination with cheap sodium persulfate (Na2S2O8) as oxidant. Herein a series of valuable acyl alkyl disulfides, important precursors for the generation of RSS-anions, and unsymmetrical dialkyl disulfides are synthesized using this direct approach. To demonstrate the potential of the method for late-stage functionalization, approved drugs and natural products were successfully C-H functionalized.

Photoinduced Radical Sulfinylation of C(sp3)–H Bonds with Sulfinyl Sulfones

“…In recent years, photocatalytic hydrogen atom transfer (HAT) has emerged as a versatile strategy for late-stage C­(sp 3 )–H functionalization. , This activation mode can conveniently transfer strong C­(sp 3 )–H bonds to carbon-centered radicals without the limitation of redox potentials of substrates. These radicals can be subjected to numerous transformations, including the formation of C–C, ,, C–N, , C–O, C–F, and C–S bonds. Photocatalytic HAT provides extensive opportunities for C–H activations and access to structural derivatives of target molecules without the need for de novo synthesis.…”

Access to Polysulfides through Photocatalyzed Dithiosulfonylation

“…As such, a transition metal free Sandmeyer‐type reductive disulfuration via aryl radical substitution on dithiosulfonates and tetrasulfides has been disclosed by our group independently [20] . The Studer group conducted research on a photocatalyzed radical C−H disulfuration of both inert alkanes and aldehydes using tetrasulfides through an intermolecular HAT process [21] (Scheme 2a, bottom right). Particularly, the groups of Wang and Ackermann recently investigated the nickel‐catalyzed disulfuration of primary alkyl bromides with tetrasulfides, yielding an innovative cross coupling approach, where the alkyl radical and Ni I /Ni III species were proposed (Scheme 2a, below the second dotted line) [22] …”

Recent advances in adhesive materials used in the biomedical field: adhesive properties, mechanism, and applications

“…Excellent adhesive performance is required in the field of devices. 42,197 Hydrogels are materials that contain a lot of water, which can provide a transport pathway for conductive ions, and are promising candidates for the manufacture of artificial skin and strain sensors. Most elastomers, which consist of semiconductors and metals, detach from each other under large strain, resulting in the breakdown of the conductive network and loss of conductive stability and sensing properties.…”