Gold/photoredox-cocatalyzed atom transfer thiosulfonylation of alkynes: Stereoselective synthesis of vinylsulfones

Copper-Catalyzed Asymmetric Nucleophilic Substitutions of TsSCF3: Synthesis of Chiral SCF3-Containing Compounds

By employing electrophilic TsSCF3 as an efficient SCF3 source, we reported Cu/SOP (chiral sulfoxide-phosphine ligand)-catalyzed enantioselective nucleophilic substitutions. Under this protocol, α-pyridyl-α-fluoro esters as latent carbon nucleophiles, compounds containing a C-SCF3 stereocenter along with azacycles and fluorine atoms, were obtained in good yields and enantioselectivities under mild conditions (up to 68% yield, 92% ee).

Bifunctionalization of α-Bromophenone: An Access to Functionalized β-Keto Thiosulfones

A simple and high-yielding strategy to produce a variety of β-keto sulfides using asymmetrical and symmetrical thiosulfonates with ketones under mild conditions is reported. It was found that the various substituted compounds, with both electron-withdrawing and electron-donating substituents, afforded a wide range of β-keto thiosulfones (α-thioaryl-β-keto sulfones) in moderate to high yields. The transformations were reliable at the gram-scale, thus illustrating their efficiency and practicality. A plausible mechanism for the protocol is also proposed.

Photocatalytic Thio/Selenosulfonylation-Bicyclization of Indole-Tethered 1,6-Enynes Leading to Substituted Benzo[c]pyrrolo[1,2,3-lm]carbazoles

The photocatalyzed radical-triggered thio/selenosulfonylation-bicyclization of indole-tethered 1,6-enynes has been established for the first time, enabling the synthesis of various previously unreported thio/selenosulfonylated benzo[c]pyrrolo[1,2,3-lm]carbazoles with moderate to good yields under mild conditions. The reaction pathway was proposed, consisting of energy transfer, homolytic cleavage, radical addition, 5-exo-dig, radical coupling, and a Mallory reaction cascade. This approach exhibits a wide substrate compatibility and excellent tolerability toward various functional groups and is characterized by its remarkable efficiency in both bond formation and annulation.

Visible-Light-Driven Unsymmetric gem-Difunctionalization of Vinyl Azides with Thiosulfonates or Selenosulfonates

Thiosulfonylation and selenosulfonylation of vinyl azides with thiosulfonates and selenosulfonates were achieved using Cu(dap)2Cl as a photosensitizer under visible-light irradiation. This reaction is the application of a vinyl azide substrate in a group transfer radical addition (GTRA) reaction, through β-difunctionalization, to obtain a variety of unsymmetric difunctionalized N-unprotected enamines.

Photocatalytic C(sp3)-H thiolation by a double SH2 strategy using thiosulfonates

Site-selective C(sp3)-H thiolation using thiosulfonates has been achieved using the decatungstate anion as a photocatalyst. Using the protocol, a variety of thiolated compounds were synthesized in good yields. The transformation consists of a cascade of double SH2 reactions, HAT and ArS group transfer, and PCET (proton-coupled electron transfer) of the leaving arylsulfonyl radical to arylsulfinic acid thus allowing the catalyst, W10O324-, to be recovered.

The Sulfinylsulfonation of alkynes for β-Sulfinyl alkenylsulfone

Here we report the first example of sulfinylsulfonation of alkynes to afford β-sulfinyl alkenylsulfone products with a broad substrate scope, excellent functional group compatibility, and high yield. Moreover, sulfinylsulfonation reaction of enyne can also be realized for constructing functionalized carbo- and heterocycles through a radical cascade cyclization process.

Synthesis of α-trifluoromethyl sulfides through fluorosulfuration of gem-difluoroalkenes

A new fluoro-sulfuration of gem-difluoroalkenes is demonstrated that occurs through a nucleophilic fluorination and subsequent interrupted electrophilic sulfuration cascade.

Hexafluoroisopropanol-Promoted Disulfidation and Diselenation of Alkyne, Alkene, and Allene

Hexafluoroisopropanol (HFIP)-promoted disulfidation and diselenation of C-C unsaturated bonds is reported. Reactions of unactivated alkyne, alkene, and allene, respectively, with disulfides or diselenides in HFIP led to desired products in good to excellent yields (up to 96%). In contrast, other solvents, such as isopropanol and dichloroethane, could not promote the same reaction. This method revealed an example of HFIP-promoted transformations under the mild conditions, which greatly highlighted the unique reactivity of this special solvent.

Transition-metal-free sulfonylations of methylthiolated alkynones to synthesize 3-sulfonylated thioflavones

A set of transition-metal-free NaI/TBHP-mediated sulfonylation cyclization reactions of methylthiolated alkynones with sulfonyl hydrazides was developed, by which various 3-sulfonylated thioflavones were prepared under mild reaction conditions.

Metal-free sulfonyl radical-initiated cascade cyclization to access sulfonated indolo[1,2-a]quinolines

A metal-free cascade reaction was developed for the synthesis of indolo[1,2-a]quinoline derivatives from arylsulfonyl hydrazides and 1-(2-(arylethynyl)phenyl)indoles in the presence of TBAI/TBHP.