Visible light-mediated organocatalyzed 1,3-aminoacylation of cyclopropane employing N-benzoyl saccharin as bifunctional reagent.

The carboamination of unsaturated molecules using bifunctional reagents is considered an attractive approach for the synthesis of nitrogen-containing compounds. However, bifunctional C-N reagents have never been employed in the carboamination of cyclopropane. In this study, we use an N-heterocyclic carbene (NHC), N-benzoyl saccharin, as a bifunctional reagent and a photoredox catalyst for a dual-catalyzed 1,3-aminoacylation of cyclopropane.

Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides C-H activation and formal phosphoryl migration.

A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity.

Synthesis of axially chiral diaryl ethers NHC-catalyzed atroposelective esterification.

Axially chiral diaryl ethers bearing two potential axes find unique applications in bioactive molecules and catalysis. However, only very few catalytic methods have been developed to construct structurally diverse diaryl ethers. We herein describe an NHC-catalyzed atroposelective esterification of prochiral dialdehydes, leading to the construction of enantioenriched axially chiral diaryl ethers.

Visible Light-Mediated Monofluoromethylation/Acylation of Olefins by Dual Organo-Catalysis.

Monofluoromethyl (CHF) motifs exhibit unique bioactivities and are considered privileged units in drug discovery. The radical monofluoromethylative difunctionalization of alkenes stands out as an appealing approach to access CHF-containing compounds. However, this strategy remains largely underdeveloped, particularly under metal-free conditions.

Catalyst-Free Trans-Selective Oxyiodination and Oxychlorination of Alkynes Employing N-X (Halogen) Reagents.

β-halogenated enol esters and ethers are versatile building blocks in organic synthesis, which has attracted increasing attention. In this study, we report the facile -oxyiodination and oxychlorination of alkynes, leading to the direct construction of versatile halogenated enol esters and ethers. This transformation features an easy operation, optimal atomic economy, a strong functional group tolerance, broad substrate scope, and excellent trans-selectivity.

DBU-Mediated Isomerization/6-π Electro-Cyclization/Oxidation Cascade of Sulfonyl-Substituted Allenyl Ketones for the Construction of Hetero-1,3,5-Trisubstituted Benzene.

1,3,5-tri-substituted benzene rings emerged with unique properties has widespread applications in materials, boosting the rapid development of their synthesis. Despite the significance, the direct construction of hetero-1,3,5-trisubstituted benzene core was far less-developed. Herein, we realized a DBU-mediated isomerization/6-π electro-cyclization/oxidative aromatization cascade of sulfonyl-substituted allenyl ketones under an air atmosphere (DBU=1,8-diazabicyclo[5.

In situ fluorogenic reaction for ratiometric fluorescent detection of alkaline phosphatase activity.

Assays utilizing in situ fluorogenic reactions provide a simple and convenient alternative approach for the detection of biological molecules and activities. In this work, a novel ratiometric fluorescent probe based on in situ fluorogenic reaction is explored and developed for alkaline phosphatase (ALP) activity sensing. An intriguing fluorogenic reaction between 2,3-diaminonaphthalene (2,3-DAN) and ascorbic acid (AA) in alkaline aqueous solutions could generate the fluorescent quinoxaline derivative.

NHC and visible light-mediated photoredox co-catalyzed 1,4-sulfonylacylation of 1,3-enynes for tetrasubstituted allenyl ketones.

The modulation of selectivity of highly reactive carbon radical cross-coupling for the construction of C-C bonds represents a challenging task in organic chemistry. N-Heterocyclic carbene (NHC) catalyzed radical transformations have opened a new avenue for acyl radical cross-coupling chemistry. With this method, highly selective cross-coupling of an acyl radical with an alkyl radical for efficient construction of C-C bonds was successfully realized.

Synthesis of Axially Chiral Aldehydes by N-Heterocyclic-Carbene-Catalyzed Desymmetrization Followed by Kinetic Resolution.

Axially chiral aldehydes have received increasing attention in enantioselective catalysis. However, only very few catalytic methods have been developed to construct structurally diverse axially chiral aldehydes. We herein describe an NHC-catalyzed atroposelective esterification of biaryl dialdehydes as a general and practical strategy for the construction of axially chiral aldehydes.

Rhodium(iii)-catalyzed diamidation of olefins via amidorhodation and further amidation.

Rh(iii)-catalyzed synthesis of vicinal diamides has been realized via elaboration of an authenticated Rh-C(sp3) species generated via initial intramolecular amidorhodation of olefins. The second amidation was achieved using both electrophilic and nucleophilic amidating reagents. The reactions proceeded under mild conditions with good yield, broad substrate scope, and excellent functional-group tolerance.

Rhodium(III)-Catalyzed Atroposelective Synthesis of Biaryls by C-H Activation and Intermolecular Coupling with Sterically Hindered Alkynes.

Reported herein is the atroposelective synthesis of biaryl NH isoquinolones by Rh -catalyzed C-H activation of benzamides and intermolecular [4+2] annulation for a broad scope of 2-substituted 1-alkynylnaphthalenes, as well as sterically hindered, symmetric diarylacetylenes. The axial chirality is constructed based on dynamic kinetic transformation of the alkyne in redox-neutral annulation with benzamides, with alkyne insertion being stereodetermining. The reaction accommodates both benzamides and heteroaryl carboxamides and proceeds in excellent regioselectivity (if applicable) and enantioselectivities (average 91.

Access to [4,3,1]-Bridged Carbocycles via Rhodium(III)-Catalyzed C-H Activation of 2-Arylindoles and Annulation with Quinone Monoacetals.

Reported herein is the Rh(III)-catalyzed annulation of N-unprotected 2-arylindoles with quinone monoacetals for the straightforward synthesis of [4,3,1]-bridged carbocycles with exclusive C(3) selectivity. Mechanistic studies, particularly deuterium-labeling experiments, suggest that the coupling likely proceeds via two-fold C-H activation with two-fold migratory insertion into the enone moieties.

Rhodium(III)-Catalyzed Enantio- and Diastereoselective C-H Cyclopropylation of N-Phenoxylsulfonamides: Combined Experimental and Computational Studies.

Cyclopropane rings are a prominent structural motif in biologically active molecules. Enantio- and diastereoselective construction of cyclopropanes through C-H activation of arenes and coupling with readily available cyclopropenes is highly appealing but remains a challenge. A dual directing-group-assisted C-H activation strategy was used to realize mild and redox-neutral Rh -catalyzed C-H activation and cyclopropylation of N-phenoxylsulfonamides in a highly enantioselective, diastereoselective, and regioselective fashion with cyclopropenyl secondary alcohols as a cyclopropylating reagent.

Rhodium-Catalyzed Enantioselective Oxidative [3+2] Annulation of Arenes and Azabicyclic Olefins through Twofold C-H Activation.

C-H bond activation is mostly limited to ortho selectivity. Activation of both ortho and meta C-H bonds constitutes a particularly important strategy for annulation, but has rarely been studied in enantioselective systems. Reported herein is rhodium(III)-catalyzed asymmetric [3+2] transannulation of arenes with 7-azabenzonorbornadienes.

Degradation mechanism study of fluoroquinolones in UV/Fe/peroxydisulfate by on-line mass spectrometry.

Antibiotics are of concern due to their prevalent detection in aquatic environment. Sulfate radical based advanced oxidation processes show a great capacity to degrade antibiotics, but the mechanisms are still unclear. In this work, the degradation mechanism of fluoroquinolones (FQs), a major group of antibiotics, in UV/Fe/PMS was deeply investigated.

Mn(i)-Catalyzed nucleophilic addition/ring expansion via C-H activation and C-C cleavage.

Mn(i)-Catalyzed synthesis of seven- or eight-membered carbocycles is disclosed via C-H activation of heteroarenes and coupling with alkyne-functionalized 1,3-cyclopentadiones or 1,3-cyclohexadiones. This n to n + 2 (n = 5, 6) ring expansion reaction proceeded via a C-H alkenylation/carbonyl addition/retro-Aldol cascade. Structurally diverse mid-sized carbocycles were constructed via cleavage of both C-H and C-C bonds in a single operation.

Rhodium(III)-Catalyzed Oxidative Allylic C-H Indolylation via Nucleophilic Cyclization.

Reported herein is a mild synthesis of 3-allylindoles via Rh(III)-catalyzed allylic C-H activation of olefins and coupling with o-alkynylanilines. The reaction proceeded via initial nucleophilic cyclization of o-alkynylanilines followed by oxidative coupling with allylic C-H bonds via an η-allyl intermediate.

Rh(III)-Catalyzed Asymmetric Synthesis of Axially Chiral Biindolyls by Merging C-H Activation and Nucleophilic Cyclization.

Enantiomeric access to pentatomic biaryls is challenging due to their relatively low rotational barrier. Reported herein is the mild and highly enantioselective synthesis of 2,3'-biindolyls via underexplored integration of C-H activation and alkyne cyclization using a unified chiral Rh(III) catalyst. The reaction proceeded via initial C-H activation followed by alkyne cyclization.

Rhodium(iii)-catalyzed diverse [4 + 1] annulation of arenes with 1,3-enynes sp/sp C-H activation and 1,4-rhodium migration.

Nitrogen-rich heterocyclic compounds have a profound impact on human health. Despite the numerous synthetic methods, diversified, step-economic, and general synthesis of heterocycles remains limited. C-H bond functionalization catalyzed by rhodium(iii) cyclopentadienyls has proven to be a powerful strategy in the synthesis of diversified heterocycles.

Manganese(I)-Catalyzed Synthesis of Fused Eight- and Four-Membered Carbocycles via C-H Activation and Pericyclic Reactions.

Pericyclic reactions have allowed facile construction of complex cycles. On the other hand, metal-catalyzed C-H activation has been established as an important strategy for rapid synthesis of complex structures. The two areas are integrated in Mn(I)-catalyzed redox-neutral coupling of 3-alkenyl- and 3-allylindoles with propargylic carbonates, which occurred via C-H allenylation with subsequent pericyclic reactions to afford fused eight- and four-membered carbocycles, respectively.

Chemodivergent Oxidative Annulation of Benzamides and Enynes via 1,4-Rhodium Migration.

Chemodivergent annulative couplings have been realized between N-methoxy benzamides and 1,3-enynes via Rh-catalyzed C-H activation and 1,4-Rh migration. Under Rh/copper catalyzed aerobic conditions, the nitrogen annulation occurred as the major pathway. The chemoselectivity was switched to the oxygen annulation under proper condition control with stoichiometric amounts of Cu(II) oxidant and NaOAc.

Mn-Catalyzed Dehydrocyanative Transannulation of Heteroarenes and Propargyl Carbonates through C-H Activation: Beyond the Permanent Directing Effects of Pyridines/Pyrimidines.

Pyridines/pyrimidines are common and effective directing groups in C-H activation. However, they are poorly functionalizable heteroarenes. Reported in this work is Mn-catalyzed dehydrocyanative transannulation between three classes of heteroarenes and propargyl carbonates.

Rhodium(III)-Catalyzed Enantioselective Coupling of Indoles and 7-Azabenzonorbornadienes by C-H Activation/Desymmetrization.

Chiral rhodium(III) cyclopentadienyl catalysts (Cp Rh ) play significant roles in asymmetric arene C-H activation. Rh/Ir-catalyzed couplings of arenes and strained rings have been well-studied, but they have been limited to racemic systems. Reported in this work is the Cp Rh /AgSbF -catalyzed enantioselective desymmetrizative C-C coupling of N-pyrimidylindoles and 7-azabenzonorbornadienes with high efficiency and enantioselectivity.

Copper-Catalyzed Cascade Aminoalkynylation-Oxidation of Propargylic Alcohols: Stereospecific Synthesis of ( Z)-2-Amino Conjugated Enynals/Enynones.

Copper-catalyzed cascade aminoalkynylation-oxidation of propargylic alcohols has been realized, sterospecifically providing an array of ( Z)-2-amino conjugated enynals/enynones in good yields under mild conditions. This transformation involves a rare 1,3-alkynyl migration of propargylic alcohols and simultaneously forms C-C, C-N, and C═O bonds. Furthermore, ( Z)-2-amino conjugated enynals were applied to efficiently synthesize 3,5-disubstituted-1 H-pyrrole-2-carbaldehyde and conjugated enynol derivatives.

Rhodium(III)-Catalyzed Redox-Neutral Synthesis of Isoquinolinium Salts via C-H Activation of Imines.

Redox-neutral synthesis of isoquinolinium salts via C-H activation of presynthesized or in situ formed imines and coupling with α-diazo ketoesters has been realized, where a zinc salt promotes cyclization as well as provides a counteranion. Under three-component conditions, both ketone and aldehydes are viable arene sources. The coupling of imines with diazo malonates under similar conditions afforded isoquinolin-3-ones as the coupling product.