Iodine(III)-Mediated Trifluoroacetylation of a C(sp2)-H or C(sp)-H Bond with Masked Trifluoroacyl Reagents.

A novel strategy for incorporating a trifluoroacetyl functionality into a range of structurally varied unsaturated bonds was developed by using PhI(OCOMe)2 as an oxidant with a masked trifluoroacyl reagent as a trifluoroacetyl radical precursor. The oxidative decarboxylation of the masked trifluoroacyl precursor followed by a tandem radical process provides versatile access to 5-exo-trig cyclization of N-arylacrylamides, direct C(sp2)-H trifluoroacetylation of quinolines, isoquinoline, 2H-indazole, and quinoxalin-2(1H)-ones, and C(sp)-H trifluoroacetylation of alkynes. This protocol is characterized by mild reaction conditions, operational simplicity, and broad functional group compatibility.

Photosensitized 1,2-Difunctionalization of Alkenes to Access ß-Amino Sulfonamides.

A metal-free photosensitized 1,2-imino-sulfamoylation of olefins by employing a tailor-made sulfamoyl carbamate as the difunctionalization reagent has been established. This protocol exhibits versatility across a broad substrate scope, including aryl and aliphatic alkenes, leading to the synthesis of diverse ß-imino sulfonamides in moderate to good yields. This method is characterized by its metal-free reaction system, mild reaction conditions, excellent regioselectivity, and high atom economy, serving as a promising platform for the preparation of ß-amino sulfonamide-containing molecules, particularly in the context of drug discovery.

Photoredox-Catalyzed Selective α-Scission of PR3-OH Radicals to Access Hydroalkylation of Alkenes.

Photoinduced generation of phosphoranyl radicals offers a versatile strategy to access a variety of synthetically valuable radicals. A long-standing challenge remains in the regulation of phosphoranyl radical to undergo α-scission pathway, although the ß-scission mode has been intensively studied. We herein developed an unprecedented protocol for selective α-scission of the P(OH)R3 radical intermediate under photocatalytic conditions. This efficient P-C bond cleavage via α-scission of the P(OH)R3 radicals has been successfully utilized in the alkylation/fluoroalkylation of alkenes.

Visible-Light-Induced, Catalyst-Free Monofluoromethyl Sulfonylation of Alkenes with Iodine(III) Reagent and DABSO.

A visible-light-induced radical relay strategy to access heterocycles bearing a monofluoromethylsufonyl moiety is reported, with PhI(OCOCH2F)2 as the CH2F radical precursor and DABSO as the SO2 source. A range of oxindoles, containing a CH2FSO2CH2- group at the C3 position, were synthesized from N-arylacrylamides in up to 97% yields. The protocol features catalyst-free photochemical tandem, mild reaction conditions, broad functional group compatibility, and good to excellent yields.

N-Chlorosulfonyl carbamate-enabled, photoinduced amidation of quinoxalin-2(1H)-ones.

Reported herein is the design and development of a new photo-induced amidation protocol with the readily available N-chlorosulfonyl carbamate as an effective amidyl-radical precursor, which could be readily prepared from commercial low-cost chlorosulfonyl isocyanate (CSI) and alcohol feedstocks. The synthetic potency of this developed protocol was well demonstrated by direct amidation of various quinoxalin-2(1H)-ones. The protocol could be further streamlined by implementing a one-pot/two-step/three-component process of CSI, alcohol, and quinoxalin-2(1H)-one, with significantly improved reaction efficiency. This methodology offers an intriguing opportunity for rapid expansion of nitrogen-containing molecular complexity, thus inspiring comprehensive exploration of a new reaction mode of CSI reagent.

Photosensitized Vicinal Sulfonylamination of Alkenes with Oxime Ester and DABCO·(SO2)2.

A metal-free photosensitized three-component reaction of oxime esters, alkenes, and DABCO·(SO2)2 was developed. This protocol could accommodate a wide substrate scope, including activated and unactivated alkenes and aryl and aliphatic carboxylic acid oxime esters, delivering a broad range of ß-amino sulfones in moderate to high yields. The insertion of SO2 as a linker moiety allows the manipulation of the functionality in the reaction process, expanding the utility of oxime esters as bifunctional reagents.

Photoredox-Catalyzed Deoxygenation of Hexafluoroacetone Hydrate Enables Hydroxypolyfluoroalkylation of Alkenes.

An unprecedented photoredox-catalyzed phosphine-mediated deoxygenation of hexafluoroacetone hydrate was established to accomplish the hydroxylpolyfluoroalkylation of electron-deficient alkenes. A range of bis(trifluoromethyl)carbinols were facilely accessed by using readily available hexafluoroacetone hydrate, instead of toxic gaseous hexafluoroacetone. A range of electron-deficient alkenes are tolerated, giving the corresponding hydro-hydroxylpolyfluoroalkylated products in moderate to high yields. Remarkable features of this synthetic strategy include operational simplicity, mild reaction conditions, excellent regioselectivity, and broad functional group tolerance. The success of this strategy relies on the delicate utilization of aldehyde/ketone-gem-diol intrinsic equilibrium, which offers an innovated open-shell pathway for the assembly of synthetically challenging polyfluoroalkylated scaffolds.

Photoredox-Catalyzed Cascade of o-Hydroxyarylenaminones to Access 3-Aminated Chromones.

Reported herein is a photoredox-catalyzed amination of o-hydroxyarylenaminones with tert-butyl ((perfluoropyridin-4-yl)oxy)carbamate, a versatile amidyl-radical precursor developed in our laboratory. This work establishes a new cascade pathway for the assembly of a range of 3-aminochromones under mild conditions. Downstream transformations of the obtained 3-aminochromones to construct diverse amino pyrimidines greatly broaden the applications of this photocatalyzed protocol.

Visible-Light-Promoted Hydroxydifluoroalkylation of Alkenes Enabled by Electron Donor-Acceptor Complex.

A catalyst-free strategy for regioselective hydroxydifluoroalkylation of alkenes with alkyl bromides was developed, affording a series of difluoroalkylated tertiary alcohols in moderate to good yields. This photocatalyst-free protocol shows broad substrate scope under mild conditions. Moreover, mechanistic studies revealed that a newly identified electron donor-acceptor complex is crucial to this transformation.

N-monosubstituted thiosemicarbazide as novel Ure inhibitors: synthesis, biological evaluation and molecular docking.

Background: Identification of novel Ure inhibitors with high potency has received considerable attention. Methodology & results: Ure inhibition was determined using the indophenol method, the affinities to Ure were estimated via surface plasmon resonance. Seventeen new plus ten known N-monosubstituted thiosemicarbazides were synthesized and identified as novel Ure inhibitors. Out of these compounds, compound b5 shows excellent activity against both crude Ure from Helicobacter pylori (IC50 = 0.04 µM) and Ure in living cell (IC50 = 0.27 µM), with the potency being over 600-fold higher than clinical used drug acetohyroxamic acid, respectively. Surface plasmon resonance demonstrated the high affinity (Kd.#x00A0;= 6.32 nM) of b5 to Ure. Conclusion: This work provides a class of novel and promising Ure inhibitors.