Herein, a palladium-catalyzed and ligand-controlled protocol for the divergent synthesis of pyrrole[2,3-b]indole and urea derivatives has been described. Pyrrole[2,3-b]indoles ("cyclization on" products) via tandem cyclization of o-alkynylanilines with isocyanides in the absence of a ligand and ureas ("cyclization off" products) via oxidative amination of anilines with isocyanides in the presence of a ligand were obtained both in moderate to good yields with high selectivity. In this chemistry, cyclic and acyclic products were easily accessed with the same starting materials under the regulation of the ligand.

Enamides and their derivatives are prominent bioactive pharmacophores found in various bioactive molecules. Herein we report a palladium-catalyzed oxidative N-alpha,beta-dehydrogenation of amides to produce a range of enamides with high yields and excellent tolerance toward different functional groups. Mechanistic studies indicate that the reaction involves allylic C(sp(3))-H activation followed by beta-H elimination. The effectiveness of this approach is demonstrated through late-stage functionalization of bioactive molecules and the synthesis of valuable compounds through product elaboration.

Palladium-catalyzed asymmetric allylic C-H functionalization is an efficient method for the construction of enantiomerically enriched allylic derivatives. This includes asymmetric allylic amination reactions for the efficient construction of chiral amines. However, the asymmetric allylic C-H amination of alkenes by Lewis basic amines is a longstanding challenge. Herein, we present a highly efficient method for the lylic C-H amination reaction. This method provides a means for synthesizing a range of biologically important enantioenriched isoindolines with high yields and excellent enantioselectivities (up to 98% yield and 98% ee).

α‐Methylene‐γ‐butyrolactone is an important skeleton in many natural products and pharmaceuticals. The factors influencing the palladium‐catalyzed asymmetric synthesis of α‐chloromethylene‐γ‐butyrolactones were investigated, including ligands, additives, the chlorine source, temperature, and solvents. We found that the reaction had broad substrate scope for the synthesis of the corresponding chiral products when the ligand, chlorine source and additives were optimized. The results will improve the catalytic synthesis of chiral α‐chloromethylene‐γ‐butyrolactones.

Direct coupling of unactivated olefins with primary alkylamines is considered to be an efficient but unknown method for the construction of complex amines. Herein we report a catalytic intermolecular oxidative amination of unactivated olefins with primary aliphatic amines based on the combination of a palladium catalyst, a bidentate phosphine ligand, and duroquinone. A range of secondary allylic amines were obtained in good yields with excellent regio- and stereoselectivity. Mechanistic control experiments revealed that the reaction proceeds by allylic C(sp3)-H activation and nucleophilic amination. The utility of the protocol is further demonstrated with the late-stage modification and streamlined synthesis of drug molecules.

A palladium-catalyzed allylic C-H oxidative allylation of N-tosylhydrazones to synthesize skipped 1,4-dienes is demonstrated. This direct allylic alkylation reaction has excellent site selectivity, tolerates a wide range of functional groups, and affords 1,4-dienes in moderate to good yield. Moreover, this olefination method allows the regio- and stereoselective synthesis of 1,4-dienes containing a trisubstituted alkene. Preliminary mechanistic studies reveal that the reaction undergoes allylic C(sp(3))-H activation and a subsequent carbene migratory insertion.

Herein, a straightforward method for the synthesis of 2,5-disubstituted selenophenes via [2+2+1] cyclization of easily accessible terminal alkynes and elemental selenium has been developed. This reaction features high atom- and step-economy, excellent regioselectivity, good functional group tolerance and the use of stable and non-toxic selenium as a selenium source. A series of control experiments suggests that the reaction might undergo Glaser coupling reaction of two molecules of alkynes, followed by insertion of H2Se and subsequent cyclization. Moreover, the newly formed products can be further converted to diverse conjugated selenophene-based derivatives, demonstrating their potential applications in organic synthesis and materials science.

Amines are prominent in natural products, pharmaceutical agents and agrochemicals. Moreover, they are synthetically valuable building blocks for the construction of complex organic molecules and functional materials. However, amines, especially aliphatic and aromatic amines with free N-H bonds, tend to coordinate with transition metals and deactivate the catalyst, posing a tremendous challenge to applying Lewis basic amines in the amination of olefins. Here we present an example of oxidative amination of simple olefins with various Lewis basic amines. The combination of a palladium catalyst, 2,6-dimethyl-1,4-benzoquinone and a phosphorous ligand leads to the efficient synthesis of alkyl and aryl allylamines. A series of allylamines were obtained with good yields and excellent regio- and stereoselectivities. Intramolecular amination to synthesize tetrahydropyrrole and piperidine derivatives was also realized. Mechanistic investigations reveal that the reaction undergoes allylic C(sp3)-H activation and subsequent functionalization.

A novel palladium-catalyzed cascade cyclization reaction of alkenyl ethers with alkynyl oxime ethers for the construction of poly-heterocyclic scaffolds has been developed, in which the electron-rich alkene moiety functions as a three-atom unit, simultaneously dealing well with the coordination and regioselectivity of electron-rich olefins under metal catalysis. The strategy features excellent regio- and chemoselectivities as well as good functional group tolerance. Moreover, the newly formed 2-isoxazolyl-2,3-dihydrobenzofuran products can be further transformed to diverse complex heterocycles, demonstrating their potential applications in organic synthesis and medicinal chemistry.

Allylamines have long been recognized as valuable synthons because of their excellent reactivity in organic synthesis. Here, an efficient amination reaction of allenyl ethers via copper/Lewis acid synergistic catalysis has been established, providing straightforward access to diverse functionalized Z-oxalylamines and E -halogenated oxalylamines in good to excellent yields with high regio- and stereoselectivities. The developed method tolerates more than 100 examples that include late-stage functionalization of bioactive molecules, and features gram-scale synthesis of oxalylamines with high turnover number (TON > 1000) under mild and simple conditions. The applicability of the protocol is further demonstrated with the construction of drug molecules.

The first examples of palladium-catalyzed allylic C-H oxidative allylation of sulfoxonium ylides to afford the corresponding conjugated dienones with moderate to good yields have been established. The features of this novel conversion include mild reaction conditions, wide substrate scope, and excellent regioselectivity.

Biodiesel as a substitute of traditional petroleum-derived liquid fuels has been put into use in recent years. However, the first generation biodiesel (fatty acid methyl esters) with high oxygen content is inconvenient for large-scale use due to its incompatible nature with fossil fuels. As a result, green biodiesel (the second generation biofuel) prepared from catalytic hydrodeoxygenation (HDO) of the first generation biodiesel has been gradually developed. The biodiesel after deoxygenation which has a great number of advantages is similar to petroleum fuel in composition, so it can be employed directly in fuel industry. To obtain the expected products, accessible production processes and suitable catalyst systems are needed. In this review, we first make an analysis on the pathways and processes of deoxygenation reactions including hydrodeoxygenation, decarboxylation and decarbonylation. Selectivity to reaction pathways has a close relationship with raw materials, catalysts or reaction conditions. The special goal of this review is to highlight the advances in the heterogeneous sulfur-free catalysts used for deoxygenation, including the sulfur-free noble metals, non-noble metals, metal phosphides, metal carbides and metal nitrides. We thoroughly discussed the different performances of these developed catalysts in the deoxygenation reactions, such as activity, selectivity and stability. Fundamental mechanisms over sulfur-free catalysts, including experimental comparison of different active phases and calculations by Density Function Theory (DFT), were also addressed. This review also involved effects of different support materials, composition, structure optimization, water and H-2 pressure on the HDO activity and silectivity, and detailed information about catalyst deactivation. It is expected that this review can provide some new design and modification strategies for fabricating highly active, selective and durable earth-abundant HDO catalysts for the substainable production of green bio-diesel.