Photocatalytic Generation of β-Fluoroalkylated α-Carbonyl Carbocations.

Nucleophilic addition to α,β-unsaturated carbonyl compounds normally occurs at the carbonyl carbon or β-carbon. The direct α-nucleophilic addition at the α-carbon can hardly be achieved due to electronic mismatch. In this work, we report the nucleophilic addition of β-fluoroalkyl α-carbonyl carbocations that are prepared via -induced redox-neutral photocatalysis.

Photocatalytic low-temperature defluorination of PFASs.

Polyfluoroalkyl and perfluoroalkyl substances (PFASs) are found in many everyday consumer products, often because of their high thermal and chemical stabilities, as well as their hydrophobic and oleophobic properties. However, the inert carbon-fluorine (C-F) bonds that give PFASs their properties also provide resistance to decomposition through defluorination, leading to long-term persistence in the environment, as well as in the human body, raising substantial safety and health concerns. Despite recent advances in non-incineration approaches for the destruction of functionalized PFASs, processes for the recycling of perfluorocarbons (PFCs) as well as polymeric PFASs such as polytetrafluoroethylene (PTFE) are limited to methods that use either elevated temperatures or strong reducing reagents.

α-Nucleophilic Addition to α,β-Unsaturated Carbonyl Compounds via Photocatalytically Generated α-Carbonyl Carbocations.

We report the photocatalytic oxidation of α-carbonyl radicals of amides or esters to the corresponding α-carbonyl carbocations through super photoreductant CBZ6 induced redox-neutral photocatalysis. The α-carbonyl radicals are formed by the β-addition of alkyl radicals generated in situ by the photocatalytic fragmentation of N-hydroxyphthalimide esters to the α,β-unsaturated amides and esters. This method enables the α-nucleophilic addition of hydroxyl or alkoxyl radicals to amides and esters without any prefunctionalization.

Photoreductive N-N Homocoupling Catalyzed by a Superphotoreductant.

Azines are valuable synthons or target molecules in organic synthesis. In this work, we report that could work as a photoreductive catalyst for the N-N homocoupling of oximes in high efficiency. This therefore enabled convenient access to a large variety of azines from the corresponding aryl and alkyl ketones, as well as aryl aldehydes in up to 99% yield.

TBN as Organic Redox Cocatalyst for Oxidative Tiffeneau-Demjanov-Type Rearrangement Using O as Sole Oxidant.

The Tiffeneau-Demjanov-type rearrangement is a ring-expansion reaction involving the cationic rearrangement of cyclic alcohols. The carbocation intermediates can be generated in situ via various means, including Wacker oxidation. In near recent reports on the reinvestiagtions by Wahl et al.

Synthesis Enabled by E-to-Z Isomerization Using CBZ6 as Energy Transfer Photocatalyst.

The reactions of -isomers and -isomers usually are different in consideration of the regioselectivity of chemoselectivity. The syntheses of -isomers are not feasible in many cases. The energy transfer (EnT) /-photoisomerization might yield the -isomers.

Photocatalytic Redox-Neutral Alkoxyacylation of Alkenes.

β-Alkoxyketones are important building blocks in organic synthesis. By utilizing CBZ6, with an oxidative potential of -2.16 V (vs the saturated calomel electrode), as a redox-neutral photocatalyst, alkoxyacylation of olefins was accomplished under the irradiation of visible light via a cationic intermediate.

Transalkylation via C-N Bond Cleavage of Amines Catalyzed by Super Organophotoreductant CBZ6.

The super organoreductant CBZ6-catalyzed tandem transalkylation-cyclization using amines as traceless radical donors and stabilizer is reported. The later-stage breaking of an N-C bond enables the transalkylation with a secondary amine as the leaving moiety. A wide range of tertiary amines were used as alkyl radical donors for the C1-C8 alkyls.

Synthesis of α-Hydroxyl and α-Amino Pyridinyl Esters via Photoreductive Dual Radical Cross-Coupling.

A method for the synthesis of α-hydroxyl and α-amino pyridinyl esters via photoreductive dual radical cross-coupling catalyzed by the super-organoreductant has been developed. A wide range of 2-pyridinylation and 4-pyridinylation of either α-ketoesters or imine derivatives has been achieved. The applications in the synthesis of pyridinyl amino-hydroxyl acids as well as a new chiral oxazoline ligand have also been accomplished.

Salicylaldehyde as an SET-HAT Bifunctional Photocatalyst for the Intermolecular Transalkylation of Phthalimide.

Salicylaldehyde works as an efficient photocatalyst for the intermolecular transalkylation of phthalimide. The well-designed dimethyl -hydroxyphthalimide ester proves to be a good alkylation reagent. It inhibits the competing intramolecular alkylation of alkylating reagent, enabling the site-specific synthesis of N-substituted phthalimide.

Iron-Catalyzed Aerobic α,β-Dehydrogenation.

An iron-catalyzed direct aerobic α,β-dehydrogenation of carbonyls has been reported. The combination of -butyl nitrite and -hydroxyphthalimide worked as the organo cocatalyst system; thus, no extra transition metal reagents are required. A large variety of lactams and flavanones as well as lactone and thiochromen-4-one could be produced via this method in high yields.

Transcriptomic and physiological analysis of the effect of octanoic acid on Meloidogyne incognita.

Root knot nematodes are the most devastating root pathogens, causing severe damage and serious economic losses to agriculture worldwide. Octanoic acid has been reported as one of the nematicides, and its mode of action is not fully understood. The main objective of this study was to elucidate the effect of octanoic acid on Meloidogyne incognita by transcriptomic analysis combined with physiological and biochemical assays.

/-Controllable Photocyclization by EnT-SET-Switch.

, a redox-neutral non-donor-acceptor-type organo-photocatalyst, presents a strong reductive potential with an oxidative potential of -2.16 V (vs SCE). It can work as a photosensitizer for both single-electron transfer and triplet energy transfer processes.

Ambient Temperature Dehydrogenative C(Ar)-H Carbonylative Lactamization of 2-Arylanilines Using DMF as C1-Source.

The direct dehydrogenative C-H cleaving carbonylative lactamization of 2-arylanilines promoted by visible light and potassium bases is reported. Solvent DMF acts as the sole carbonyl source in the absence of an oxidant. The irreversible release of hydrogen gas drags this reaction to the stable phenanthridinone products.

Reductive Cleavage of C-X or N-S Bonds Catalyzed by Super Organoreductant CBZ6.

The reductive cleavage of C(Ar)-X bonds is the key step for the cross coupling of Ar-X with other groups. In this work, under the irradiation of 407 nm LEDs using sodium formate as reductant and thiol as hydrogen atom transfer agent, a variety of (hetero)aryl chlorides, bromides, and iodides could be reduced to corresponding (hetero)arenes. The key intermediates, aryl radicals, could be trapped by either hydrogen, phosphite, or borates.

Synthesis of carbinoxamine α-C(sp)-H 2-pyridylation of O, S or N-containing compounds enabled by non-D-A-type super organoreductants and sulfoxide- or sulfide HAT reagents.

The radical cations of tertiary amines (RN) have been well-established as the precursors of HAT reagents in photochemical transformations. Similarly, thiols and thioacids bearing SH groups have also been widely applied as HAT reagents. Despite the fact that sulfoxides (RSO) and sulfides (RSR) also bear lone pairs of electrons, these compounds have been barely reported as HAT reagents in photocatalysis.

Butyl Nitrite as a Twofold Hydrogen Abstractor for Dehydrogenative Coupling of Aldehydes with -Hydroxyimides.

A synthetically practical transition metal/catalyst/halogen-free dehydrogenative coupling of aldehydes with -hydroxyimides promoted solely by butyl nitrite under mild conditions was developed. Butyl nitrite generates two radicals (BuO and NO) and thus works as a twofold hydrogen abstractor. A diverse array of -hydroxyimide esters were prepared from either aliphatic or aromatic aldehydes.

Direct Synthesis of β-Amino Aldehydes from Linear Allylic Esters Using O as the Sole Oxidant.

A tandem isomerization--Markovnikov oxidation of linear allylic imidic esters is developed using bis(benzonitrile)palladium chloride as the catalyst and O as the sole oxidant, regiospecifically giving β-amino aldehydes as the product. -Butyl nitrite works as a simple, and the only, redox cocatalyst. BuOH proves to be a crucial solvent for achieving excellent yield and specificity toward -Markovnikov aldehyde products.

CBZ6 as a Recyclable Organic Photoreductant for Pinacol Coupling.

A recyclable organic photoreductant (1 mol % )-catalyzed reductive (pinacol) coupling of aldehydes, ketones, and imines has been developed. Irradiated by purple light (407 nm) using triethylamine as an electron donor, a variety of 1,2-diols and 1,2-diamines could be prepared. The oxidation potential of the excited state of is established as -1.

Iron-Catalyzed α,β-Dehydrogenation of Carbonyl Compounds.

An iron-catalyzed α,β-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,β-unsaturated counterparts in a simple one-step reaction with high yields.

Discovery of Oxygen α-Nucleophilic Addition to α,β-Unsaturated Amides Catalyzed by Redox-Neutral Organic Photoreductant.

The conjugate additions of oxygen-centered nucleophiles to conjugate acceptors are among the most powerful C-O bond formation reactions. The conjugate addition normally takes place at the β-position carbon to the electron-withdrawing group, resulting in the formation of a stabilized carbanion intermediate that can be quenched by proton or electrophiles to form the β-addition (i.e.

BuOK-Promoted Cyclization of Imines with Aryl Halides.

A transition-metal-free indole synthesis using radical coupling of 2-halotoluenes and imines via the later-stage C-N bond construction was reported for the first time. It includes an aminyl radical generation by C-H cleaving addition of 2-halotoluenes to imines via the carbanion radical relay and an intramolecular coupling of aryl halides with aminyl radicals. One standard condition can be used for all halides including F, Cl, Br, and I.

Visible-Light-Induced, Base-Promoted Transition-Metal-Free Dehalogenation of Aryl Fluorides, Chlorides, Bromides, and Iodides.

We report a simple and efficient visible-light-induced transition-metal-free hydrogenation of aryl halides. The combined visible light and base system is used to initiate the desired radical-mediated hydrogenation. A variety of aryl fluorides, chlorides, bromides, and iodides could be reduced to the corresponding (hetero)arenes with excellent yields under mild conditions.

CuSO-Catalyzed dual annulation to synthesize O, S or N-containing tetracyclic heteroacenes.

In this work, CuSO4 is utilized as a practical redox catalyst for tandem dual annulation in the synthesis of indole-fused tetracyclic heteroacenes, which are important skeletons in both medicinal chemistry and materials chemistry. The preparation of such skeletons in a convenient and efficient manner is in high demand. This method realizes the modular synthesis of benzofuro-, benzothieno-, and indoloindoles from abundant feedstocks such as 2-halobenzyl halides and nitrile derivatives in up to 99% yields, providing a rapid access to diverse indole-fused heteroacenes with biological or optoelectronic properties.

Deprotonated Salicylaldehyde as Visible Light Photocatalyst.

Salicylaldehyde is established as an efficient visible light photocatalyst for the first time. Compared to other simple aldehyde analogies, salicylaldehyde has a unique deprotonative red-shift from 324 to 417 nm and gives rise to the remarkable increase of fluorescence quantum from 0.0368 to 0.