Enantioselective Ni-Catalyzed Electrochemical Synthesis of Biaryl Atropisomers.

A scalable enantioselective nickel-catalyzed electrochemical reductive homocoupling of aryl bromides has been developed, affording enantioenriched axially chiral biaryls in good yield under mild conditions using electricity as a reductant in an undivided cell. Common metal reductants such as Mn or Zn powder resulted in significantly lower yields in the absence of electric current under otherwise identical conditions, underscoring the enhanced reactivity provided by the combination of transition metal catalysis and electrochemistry.

Nickel-Catalyzed Electrochemical Reductive Relay Cross-Coupling of Alkyl Halides to Aryl Halides.

A highly regioselective Ni-catalyzed electrochemical reductive relay cross-coupling between an aryl halide and an alkyl halide has been developed in an undivided cell. Various functional groups are tolerated under these mild reaction conditions, which provides an alternative approach for the synthesis of 1,1-diarylalkanes.

Electrochemistry-Enabled Ir-Catalyzed Vinylic C-H Functionalization.

Synergistic use of electrochemistry and organometallic catalysis has emerged as a powerful tool for site-selective C-H functionalization, yet this type of transformation has thus far mainly been limited to arene C-H functionalization. Herein, we report the development of electrochemical vinylic C-H functionalization of acrylic acids with alkynes. In this reaction an iridium catalyst enables C-H/O-H functionalization for alkyne annulation, affording α-pyrones with good to excellent yields in an undivided cell.

Electrochemical Radical Formyloxylation-Bromination, -Chlorination, and -Trifluoromethylation of Alkenes.

Given the versatility and value of the structurally diverse organohalides and CF-containing compounds in organic synthesis, we reported a green, oxidant-free electrochemical method using undivided electrochemical cells for radical bromination, chlorination and trifluoromethylation-formyloxylation of the various alkenes with readily available halogen radical (NaCl, NaBr), trifluoromethyl radical (CFSONa) sources, and DMF as formyloxylation reagents. The protocol is operationally simple and robust and the Cl, Br or CF was directly oxidized at the anode, obviating the need for exogenous chemical oxidants.

Nickel-Catalyzed Thiolation of Aryl Halides and Heteroaryl Halides through Electrochemistry.

Transition-metal-catalyzed coupling reactions are useful tools for synthesizing aryl sulfur compounds. However, conventional transition-metal-catalyzed thiolation of aryl bromides and chlorides typically requires the use of strong base under elevated reaction temperature. Herein, we report the first examples of nickel-catalyzed electrochemical thiolation of aryl bromides and chlorides in the absence of an external base at room temperature using undivided electrochemical cells.

Identification of active compounds from Caesalpinia sappan L. extracts suppressing IL-6 production in RAW 264.7 cells by PLS.

Ethnopharmacological Relevance: Caesalpinia sappan L. is distributed in Southeast Asia and also used as herbal medicine for the treatment of various diseases such as burning sensations, leprosy, dysentery, osteoarthritis and rheumatoid arthritis (RA). The overproduction of IL-6 plays an important role in the prognosis of RA, but the active compounds from the extracts of Caesalpinia sappan L.