The incorporation of additional Csp3 atoms into candidate drugs may enhance their pharmacological properties. Nevertheless, it remains challenging to construct desired Csp3-Csp3 bonds efficiently and practically. The present article reports a novel Csp3-Csp3 bond-forming reaction of 2-aryl/alkyl substituted aziridines with gem-diborylalkanes under tranisiton metal free conditions. A wide range of γ-gem-diboronate esters substituted amines can be accessed in good yield and regioselectivity. The results demonstrated that various aziridines could react with gem-diborylalkanes in the presence of LiTMP as the base within 15 min at ambient temperature.

An iron-catalyzed [4 ​+ ​2] annulation of amidines with α,β-unsaturated ketoxime acetates is described. This strategy employs amidines as CN units and provides a new protocol for the construction of 2,4,6-trisubstituted pyrimidines under batch and continuous flow conditions in moderate to good yields, exhibiting good functional group tolerance, scalability and operational simplicity.

An organocatalytic Markovnikov-type bromo-aminoxidation of styrene derivatives was achieved by using in-situ-generated bromine and N-oxyl radicals, and the desired products were obtained in moderate to good yields. The bromine radical was generated from phenyliodine(III) bis(3-bromopropionate) through consecutive decarboxylation and deethylenation reactions via an organocatalytic SET process. Phenyliodine(III) bis(3-bromopropionate) also served as the oxidant for the generation of the N-oxyl radicals, while the N-oxyl radical was also crucial for the generation of the key β-enaminyl radical intermediate that was required for the SET process.

The known methods for the preparation of acylphosphine oxides and polyfluorobenzene-substituted triarylphosphines need to utilize PCl3, while the chlorine-free methods are not reported. In this work, we report a chlorine-free method by one-pot three-component reaction of white phosphorus (P4), dilithio reagents, and acyl chlorines or polyfluorobenzenes for the synthesis of biphenyl-based acylphosphine oxides and phosphines. This reaction is green and environmentally friendly compared with the traditional method, because it avoids the use of Cl2 and the discharge of a large amount of waste gas and waste acid. These two products have potential applications as photoinitiators in photopolymerization or as organophosphorus ligands in catalytic reactions.

The construction of N-fused polycyclic compounds at room temperature via the combination of transition-metal catalyst and photocatalyst has been reported. This novel work has successfully realized LED irradiated C−H activation of iodonium ylides. The strategy shows wide substrate scope and ideal functional group tolerance. Our work would be useful for the construction of various heterocyclic compounds.

A novel protocol for the preparation of highly functionalized 2-azabicyclo[3.3.1]nonane (morphan) derivatives via a multicomponent cascade reaction, involving 3-formylchromones, 2-naphthols, and enaminones in the ionic liquid [BMIM]PF6 as the solvent and promoted by 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU), was developed, which involved the cleavage of one C–O bond and formation of four bonds (1 ​C–O, 1 ​C–N, and 2 ​C–C bonds). As a result, a series of morphan derivatives were produced through a cascade reaction, including a sequence of 1,2-addition, enol-keto tautomerization, Michael addition, dehydration, another Michael addition, imine-enamine tautomerization, and N-alkylation reactions, which were accompanied by a ring-opening reaction. This protocol was suitable for combinatorial and parallel syntheses of natural product-like morphan compounds in a one-pot reaction rather than through tedious multi-step reactions.

A visible-light-promoted formal [2 ​+ ​2 + 1] cyclization of N-aryl glycines with quinoxalin-2(1H)-ones to synthesize tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones have been developed. The protocol features operational simplicity, mild reaction conditions with blue LED light employing Ru(bpy)3Cl2.6H2O as a photoredox catalyst, a combination of O2 from air and Cu(OAc)2 as the oxidant and broad substrate applicability.

The development of a highly efficient, selective and atom-economical method for the construction of allylic amines are a challenge in green synthetic chemistry. In a recent work published in Nature Catalysis, Lei, Qi, and co-workers reported that the combination of a photoredox catalyst and cobaloxime catalyst enables site-selective allylic amination of various olefins with secondary alkyl amines, affording the valuable tertiary aliphatic allylamines, without the need for external oxidants.

Transition-metal-catalyzed cross-coupling reactions as very efficient and atom-economical approaches have been widely used to build up complex heterocyclic compounds. However, modification of 2-oxyl benzimidazole skeleton using maleimide compounds via C–H activation has remained unprecedented. Herein, we developed a rhodium(III)-catalyzed [5 ​+ ​1] cascade spiroannulation to construct diversified novel benzimidazole-incorporated spirosuccinimide derivatives from 2-oxyl benzimidazoles and maleimides.

Metal- and oxidant-free alkenyl C–H thiolation enabled by the azo group had been established for the modular synthesis of tetrasubstituted acyclic olefins. The reaction was performed under mild reaction conditions with a broad substrate scope. The intramolecular 6-membered hydrogen-bonding network accounts for the observed excellent stereo-control.

Non-covalent interactions are of significance in supramolecular chemistry and biochemistry, while synthetic procedures driven by these weak interactions remain challenging and rare. Inspired by the lone pair-π interaction presence in the Z-DNA structure, a light-induced regioselective sulfonation of ethers taking advantage of the lone pair-π interaction between the oxygen of ethers and sulfonyl chlorides has been disclosed. Moreover, this strategy is also applicable to the sulfonation of aniline derivatives. Features of the methods include readily accessible starting materials, high atom-economy, green and photocatalyst-free conditions and broad functional group tolerance. Mechanism studies suggest that the lone pair-π interaction plays an important role to initiate the transformation.

The [2,3]- and [1,2]-sigmatropic rearrangement reactions between pyridotriazoles and sulfides catalyzed by rhodium(II) were investigated. The utilization of pyridotriazoles as the carbene precursors in this kind of reaction efficiently constructed the C(sp3)-S and C(sp3)-Se bond with broad substrate scope and great functional group tolerance.

A novel and green route have been developed for the electrochemical synthesis of 3-halogenated spiro[4.5]trienones based on dearomative spirocyclization of alkynes with NaX (Br, I) as the halogen source. This transformation was performed in an undivided cell under mild conditions. A wide range of substituted 3-halogenated spiro[4.5]trienones products was prepared in moderate-to-good yields, showing a broad scope and functional group tolerance. In addition, this approach was further extended to access fused tricyclic 6,7-dihydro-3H-pyrrolo[2,1-j]quinoline-3,9(5H)-diones.

The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals, and the nitrile groups are versatile synthetic intermediates to other functionalized compounds. Herein, the asymmetric reduction of α,β-unsaturated nitriles with water as a hydrogen source is reported. The reaction is catalyzed by the complex of [Ir(COD)Cl]2 and (Ra, S)-Ph-Bn-SiPhox, and allows the preparation of useful enantioenriched chiral 3,3-disubstituted propionitriles with high optical purities in mild conditions.

A strategy for the synthesis of α-carboline derivatives from indole-3-carboxaldehydes and 3-aminocyclohex-2-enones under metal-free conditions has been developed. The combination use of phenyliodine (III) diacetate (PIDA) and benzoic acid could significantly facilitate the corresponding [3 ​+ ​3] annulation process. This newly developed strategy featured unextraordinary chemoselectivity, good functional group tolerance and the preservation of the carbonyl group of the ketone substrates, which offers the possibility for further transformation of the products.

A highly efficient, transition-metal- and light-free approach to polyheterocycles via regioselective cascade radical cyclization is developed. The redox-neutral protocol has a broad substrate scope with good functional group tolerance and probably undergoes a SET process, which is initiated by catalytic amounts of quinone in combination with 2.0 equiv. of Cs2CO3.

Core-shell structured magnetic wrinkled organosilica-based metal-enzyme integrated catalysts were synthesized, and their catalytic performances were studied in the chemoenzymatic dynamic kinetic resolution of chiral amines in an organic solvent, as well as in the chemoenzymatic synthesis of chiral alcohols in water. Structure-performance studies revealed the important influence of their tunable structure and composition on the optimization of activity, stability, and recyclability in chemoenzymatic catalysis.

A green efficient photoredox-catalyzed decarboxylative alkynylation of carboxylic acids with alkynyl bromides has been developed. This broadly applicable protocol is presented wherein α-amino, aliphatic and α-oxy acids are converted into useful alkynylation products. The commercially-available organic photocatalyst 4CzIPN is used as the photocatalyst, organic base DBU is utilized as the base, and DMSO serves as solvent. This strategy features mild conditions, is metal-free, and is environmentally friendly. The batch and continuous-flow protocols described were applied to obtain a broader substrate scope of functionalization (more than 50 examples). Furthermore, we demonstrate that the use of microflow technology enhanced and intensified the reaction process, achieving significantly reduced reaction times (i.e., 10 ​min of residence time).

A copper-catalyzed three-component reaction of diazo compounds, nitriles, and azodicarboxylates to construct 2,3-dihydro-1,2,4-triazoles is reported. Key to the success is the utilization of azodicarboxylates to trap the in-situ formed nitrile ylides from diazo compounds by [3 ​+ ​2]-cycloaddition. Both the acceptor-only and donor-acceptor diazo compounds are all tolerated to the strategy. The synthetic value of this protocol is illustrated by gram-scale synthesis and valuable transformation of the obtained 2,3-dihydro-1,2,4-triazoles.

A highly efficient and mild method for [3 ​+ ​2] cycloaddition of β-sulfonyl-α,β-unsaturated ketones with terminal allenoates was well-explored and developed. The reactions were successfully performed by applying multifunctional chiral phosphine P6 which was screened from eight chiral phosphorus reagents to finally result in a variety of enantioenriched sulfone-substituted cyclopentenes with two chiral centers (up to 81% yield with 94% ee). Moreover, 2.5 ​mol% catalytic equivalents were proved to be feasible when this reaction was performed on a 10 ​mmol scale.