Copper-Catalyzed Oxyfluorosulfonylation of β,γ-Unsaturated Oximes with Sulfur Dioxide and Selectfluor for Isoxazoline-Functionalized Aliphatic Sulfonyl Fluorides

In this report, we describe a copper-catalyzed cascade reaction involving oxygen radical-induced cyclization/SO2 insertion/fluorination of β,γ-unsaturated oximes with sulfur dioxide and Selectfluor under mild conditions for the synthesis of isoxazoline-functionalized aliphatic sulfonyl fluorides. The synthetic potential of these compounds has been evaluated through diverse SuFEx reactions.

Electroreductive hydroxy fluorosulfonylation of alkenes

An electroreductive strategy for radical hydroxyl fluorosulfonylation of alkenes with sulfuryl chlorofluoride and molecular oxygen from air is described. This mild protocol displays excellent functional group compatibility, broad scope, and good scalability, providing convenient access to diverse β-hydroxy sulfonyl fluorides. These β-hydroxy sulfonyl fluoride products can be further converted to valuable aliphatic sulfonyl fluorides, β-keto sulfonyl fluorides, and β-alkenyl sulfonyl fluorides. Further, some of these products showed excellent inhibitory activity against Botrytis cinerea or Bursaphelenchus xylophilus, which could be useful for potent agrochemical discovery. Preliminary mechanistic studies indicate that this transformation is achieved through rapid O2 interception by the alkyl radical and subsequent reduction of the peroxy radical, which outcompete other side reactions such as chlorine atom transfer, hydrogen atom transfer, and Russell fragmentation.

New Chemical Transformations Involving SO2 F2 -Mediated Alcohol Activation

Sulfuryl fluoride is a gas produced on a multi-ton scale for its use as a fumigant. In the last decades, it has gained interest in organic synthesis as a reagent with unique properties in terms of stability and reactivity when compared to other sulfur-based reagents. Sulfuryl fluoride has not only been used for sulfur-fluoride exchange (SuFEx) chemistry but also encountered applications in classic organic synthesis as an efficient activator of both alcohols and phenols, forming a triflate surrogate, namely a fluorosulfonate. A long-standing industrial collaboration in our research group drove our work on the sulfuryl fluoride-mediated transformations that will be highlighted below. We will first describe recent works on metal-catalyzed transformations from aryl fluorosulfonates while emphasizing the one-pot processes from phenol derivatives. In a second section, nucleophilic substitution reactions on polyfluoroalkyl alcohols will be discussed and the value of polyfluoroalkyl fluorosulfonates in comparison to alternative triflate and halide reagents will be brought to light.

Access to Benzocyclic Boronates via Light-Promoted Intramolecular Arylborylation of Alkenes

Benzocyclic boronates have attracted increasing research interest in drug chemistry and organic synthesis in recent years. Herein, we report a facile access to benzocyclic boronates through photopromoted intramolecular arylborylation of allyl aryldiazonium salts. This simple protocol features a broad scope, allowing the formation of variously functionalized borates bearing dihydrobenzofuran, dihydroindene, benzothiophene, and indoline skeletons under mild and sustainable conditions.

Photo-organocatalytic Synthesis of β-Keto Sulfonyl Fluorides via Radical Fluorosulfonylation of Vinyl Acetates

A metal-free synthesis of useful β-keto sulfonyl fluorides has been established via radical fluorosulfonylation of ketone-derived vinyl acetates under photoredox organocatalysis by using 1-fluorosulfonyl benzoimidazolium (FABI) as the fluorosulfonyl radical source and oxygen-doped anthanthrene (ODA) as the photocatalyst. A series of aryl and alkyl β-keto sulfonyl fluorides as well as cyclic analogues can be readily obtained in moderate to high yields from widely available ketone starting materials.

Fluorosulfonyl radicals: new horizons for the synthesis of sulfonyl fluorides

Recent advances in the generation of fluorosulfonyl radicals toward sulfonyl fluorides are highlighted.