tert-Butyl Hydroperoxide (TBHP)-Initiated Vicinal Sulfonamination of Alkynes: A Radical Annulation toward 3-Sulfonylindoles

The Oxidative State of Cysteine Thiol 144 Regulates the SIRT6 Glucose Homeostat

Control of glucose homeostasis plays a critical role in health and lifespan and its dysregulation contributes to inflammation, cancer and aging. NAD + dependent Sirtuin 6 (SIRT6) is a glucose homeostasis regulator in animals and humans and its regulation at the molecular level is unknown. Here, we report that a cysteine thiol redox sensor contributes to the role of SIRT6 in controlling glucose homeostasis. Sulfenylation of SIRT6 occurs in THP1 cells and primary human promonocytes during inflammation and in splenocytes from mice with sepsis. Inhibiting xanthine oxidase, a major reactive oxygen species (ROS) contributor during acute inflammation, reduces sulfenylation of SIRT6, glucose transporter Glut1 expression, glucose uptake, and glycolysis. A block in glycolysis associated with monocyte deactivation by endotoxin, a process contributing to immunometabolic paralysis in human and mouse sepsis monocytes, can be reversed by increasing H₂O₂ and sulfenylating SIRT6. Mutation analysis of SIRT6 Cys144, which lies in its phylogenetically conserved zinc-associated Cys-X-X-Cys motif near the catalytic domain of the protein, decreases SIRT6 deacetylase activity and promotes glycolysis. These results suggest that direct and reversible cysteine thiol 144 may play a functional role in SIRT6-dependent control over monocyte glycolysis, an important determinant of effector innate immune responses.

Nickel-Catalyzed Intermolecular Carbosulfonylation of Alkynes via Sulfonyl Radicals

β,β-Disubstituted vinyl sulfones were obtained with complete regio- and stereocontrol in a multicomponent reaction involving alkynes, organoboronic acids, and sulfonyl chlorides in the presence of a nickel catalyst. The reaction proceeds via sulfonyl radicals generated in situ under mild reaction conditions.

Transition-metal-free, visible-light-mediated cyclization of o-azidoarylalkynes with aryl diazonium salts

A visible-light promoted transformation of o-azidoarylalkynes and aryl diazonium salts for the synthesis of unsymmetrical 2,3-diaryl-substituted indoles under transition-metal-free conditions was described.

Synthesis of N-alkyl-3-sulfonylindoles and N-alkyl-3-sulfanylindoles by cascade annulation of 2-alkynyl-N,N-dialkylanilines

Divergent synthesis of N-alkyl-3-sulfonylindoles and N-alkyl-3-sulfanylindoles from 2-alkynyl-N,N-dialkylanilines and sulfonyl hydrazides has been described.

Transition-metal-free, visible-light induced cyclization of arylsulfonyl chlorides with o-azidoarylalkynes: a regiospecific route to unsymmetrical 2,3-disubstituted indoles

A visible-light-catalyzed synthesis of unsymmetrical 2,3-diaryl-substituted indoles from arylsulfonyl chlorides and o-azidoarylalkynes at room temperature has been discovered.

tert-Butyl nitrite-mediated vicinal sulfoximation of alkenes with sulfinic acids: a highly efficient approach toward α-sulfonyl ketoximes

A novel vicinal sulfoximation of alkenes was achieved under mild and metal-free conditions by using readily available sulfinic acids as the sulfonating agent and tert-butyl nitrite (TBN) as the radical initiator and the oxime source.

Metal-Free Radical Oxidative Cyclization of o-Azidoaryl Acetylenic Ketones with Sulfinic Acids To Access Sulfone-Containing 4-Quinolones

A novel one-pot synthesis of sulfone-containing 4-quinolones with easily available sulfinic acids as sulfonylating precursors is described. This reaction is characterized by mild reaction conditions, high functional-group tolerance and amenability to gram-scale synthesis.

Collective Synthesis of 3-Acylindoles, Indole-3-carboxylic Esters, Indole-3-sulfinic Acids, and 3-(Methylsulfonyl)indoles from Free (N-H) Indoles via Common N-Indolyl Triethylborate

A general and direct C3 functionalization of free (N-H) indoles with readily available electrophiles such as acid chlorides, chloroformates, thionyl chloride, and methylsulfonyl chloride via a common N-indolyl triethylborate intermediate is reported. The reaction proceeds smoothly under mild conditions in up to 93% yield. Indoles with substituents at the C2, C4, C5, C6, and C7 positions are well tolerated. The easy accessibility of a variety of important 3-acylindoles, indole-3-carboxylic esters, indole-3-sulfinic acids, and 3-(methylsulfonyl)indoles demonstrates the high degree of compatibility and practicability of this method.