Catalytic oxidative cross-dehydrogenative coupling between unactivated C(sp2)–H and C(sp3)–H bonds is achieved by the cobalt-catalyzed o-alkylation reaction of aromatic carboxamides containing (pyridin-2-yl)isopropyl amine (PIP–NH2) as a N,N-bidentate directing group. Many different C(sp3)–H bonds in alkanes, toluene derivatives and even in the α-position of ethers and thioethers can be used as coupling partners. This method has a broad substrate scope and the tolerance of various functional groups.

Given the importance of amines in a large number of biologically active natural products, active pharmaceutical ingredients, agrochemicals, and functional materials, the development of efficient C–N bond-forming methods with wide substrate scope continues to be at the frontier of research in synthetic organic chemistry. Here, we present a general and fundamentally new synthetic approach for the direct, transition-metal-free preparation of symmetrical and unsymmetrical diaryl-, arylalkyl-, and dialkylamines that relies on the facile single or double addition of readily available C-nucleophiles to the nitrogen atom of bench-stable electrophilic aminating agents. Practical single and double polarity reversal (i.e., umpolung) of the nitrogen atom is achieved using sterically and electronically tunable ketomalonate-derived imines and oximes. Overall, this novel approach represents an operationally simple, scalable, and environmentally friendly alternative to transition-metal-catalyzed C–N cross-coupling methods that are currently used to access structurally diverse secondary amines.

An oxy-palladation, formal Wagner–Meerwein rearrangement and fluorination cascade has been established for generating fluorinated oxazolidine-2,4-diones and oxazolidin-2-ones. The reaction has a broad substrate scope in which both aryl and alkyl groups can be utilized as efficient migrating groups. Experimental evidence suggests that the reaction is initiated by anti-oxy-palladation of the olefin, followed by oxidative generation of an alkyl PdIV intermediate and a concerted migration–fluorination.

•20 pyrazoline derivatives have been synthesized and all are novel except C1.•Their anti-cancer activities were evaluated for the first time.•Selectivity and cytotoxicity of representative compounds were tested.•Molecular docking and QSAR discussions indicated breaking the limit of previous pattern to get the most potent C6.A series of novel dioxin-containing triaryl pyrazoline derivatives C1–C20 have been synthesized. Their B-Raf inhibitory and anti-proliferation activities were evaluated. Compound C6 displayed the most potent biological activity against B-RafV600E and WM266.4 human melanoma cell line with corresponding IC50 value of 0.04 μM and GI50 value of 0.87 μM, being comparable with the positive controls and more potent than our previous best compounds. Moreover, C6 was selective for B-RafV600E from B-RafWT, C-Raf and EGFR and low toxic. The docking simulation suggested the potent bioactivity might be caused by breaking the limit of previous binding pattern. A new 3D QSAR model was built with the activity data and binding conformations to conduct visualized SAR discussion as well as to introduce new directions. Stretching the backbone to outer space or totally reversing the backbone are both potential orientations for future researches.A series of novel dioxin-containing triaryl pyrazoline derivatives C1–C20 have been synthesized with their B-Raf inhibitory activity and anti-proliferation activity tested. Selectivity and cytotoxicity of representative compounds have been tested. The docking simulation and 3D QSAR model indicated breaking the limit of previous binding pattern.

The development of environmentally benign, operationally simple, and economically viable synthetic methodologies has been a great challenge in organic synthesis. Group-assisted purification (GAP) chemistry was established to enable the synthesis of organic compounds without using traditional purification technologies, such as column chromatography and recrystallization. This concept/technology should encourage the synthetic community to make more efforts on searching for environmentally benign reagents and reactions to reduce the waste generated from silica and solvents, particularly toxic solvents; also, to reduce production/synthesis expenses, manpower, and energy. This review will discuss the GAP concept/technology and related reactions that were mainly conducted in the PI's laboratories after 2010.

Cobalt-catalyzed decarboxylative cross-coupling of oxazoles and thiazoles with α-oxocarboxylic acids was developed through an sp2 C–H bond functionalization process. This work represents the first example of cobalt-catalyzed decarboxylative C–H bond functionalization and provides an efficient means of building some important bioactive heteroaryl ketone derivatives.

The development of environmentally benign, operationally simple, and economically viable synthetic methodologies has been a great challenge in organic synthesis. Group-assisted purification (GAP) chemistry was established to enable the synthesis of organic compounds without using traditional purification technologies, such as column chromatography and recrystallization. This concept/technology should encourage the synthetic community to make more efforts on searching for environmentally benign reagents and reactions to reduce the waste generated from silica and solvents, particularly toxic solvents; also, to reduce production/synthesis expenses, manpower, and energy. This review will discuss the GAP concept/technology and related reactions that were mainly conducted in the PI's laboratories after 2010.