Catalytic dehydrogenative cross-coupling: forming carbon-carbon bonds by oxidizing two carbon-hydrogen bonds

3.1. C-M and X-H as Nucleophiles 1806 3.2. C-H and X-M as Nucleophiles 1809 3.2.1. C-Halogen Bond Formations 1809 3.2.2. C-O Bond Formations 1812 3.3. C-H and X-H as Nucleophiles 1812 3.3.1. C-O Bond Formations 1812 3.3.2. C-N Bond Formations 1815 4. Oxidative X-X Bond Formations between Two Nucleophiles 1819 5. Conclusions 1819 Author Information 1819 Biographies 1819 Acknowledgment 1820 References 1820

Bond Formations between Two Nucleophiles: Transition Metal Catalyzed Oxidative Cross-Coupling Reactions

Iron Catalysis in Organic Synthesis

The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C–C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of...

Advances in Synthetic Applications of Hypervalent Iodine Compounds

The selective oxidation of C-H bonds and the use of O(2) as a stoichiometric oxidant represent two prominent challenges in organic chemistry. Copper(II) is a versatile oxidant, capable of promoting a wide range of oxidative coupling reactions initiated by single-electron transfer (SET) from electron-rich organic molecules. Many of these reactions can be rendered catalytic in Cu by employing molecular oxygen as a stoichiometric oxidant to regenerate the active copper(II) catalyst. Meanwhile, numerous other recently reported Cu-catalyzed C-H oxidation reactions feature substrates that are electron-deficient or appear unlikely to undergo single-electron transfer to copper(II). In some of these cases, evidence has been obtained for the involvement of organocopper(III) intermediates in the reaction mechanism. Organometallic C-H oxidation reactions of this type represent important new opportunities for the field of Cu-catalyzed aerobic oxidations.

Copper-Catalyzed Aerobic Oxidative C ? H Functionalizations: Trends and Mechanistic Insights

Easily available and nontoxic FeCl3 catalyzes intramolecular oxidative coupling for the direct construction of the phenanthrene ring using meta-chloroperbenzoic acid as sole oxidant at room temperature in excellent yields. The mechanistic investigations show that FeCl3-catalyzed coupling proceeds through the heterolytic coupling (A+ + B). The catalytic approach has been applied to intermolecular biaryl coupling of 2-naphthols and phenol ether.

Iron(III) chloride catalyzed oxidative coupling of aromatic nuclei.

Six known β-carboline, dihydro-β-carboline, and tetrahydro-β-carboline alkaloids and a series of their derivatives were designed, synthesized, and evaluated for their anti-tobacco mosaic virus (TMV) and fungicidal activities for the first time. All of the alkaloids and some of their derivatives (compounds 3, 4, 14, and 19) exhibited higher anti-TMV activity than the commercial antiviral agent Ribavirin both in vitro and in vivo. Especially, the inactivation, curative, and protection activities of alkaloids Harmalan (62.3, 55.1, and 60.3% at 500 μg/mL) and tetrahydroharmane (64.2, 57.2, and 59.5% at 500 μg/mL) in vivo were much higher than those of Ribavirin (37.4, 36.2, and 38.5% at 500 μg/mL). A new derivative, 14, with optimized physicochemical properties, obviously exhibited higher activities in vivo (50.4, 43.9, and 47.9% at 500 μg/mL) than Ribavirin and other derivatives; therefore, 14 can be used as a new lead structure for the development of anti-TMV drugs. Moreover, most of these compounds exhibit...

Synthesis and antiviral and fungicidal activity evaluation of β-carboline, dihydro-β-carboline, tetrahydro-β-carboline alkaloids, and their derivatives.

Racemic phenanthroindolizidine alkaloids tylophorine, antofine, and deoxytylophorinine, and optically pure alkaloids S-(+)-tylophorine and R-(-)-tylophorine were synthesized and evaluated for their antiviral activities against tobacco mosaic virus (TMV). Further salinization modifications based on tylophorine increased stability and water solubility and improved the antiviral activity in application. The bioassay results showed that most of these synthesized compounds showed higher antiviral activity against TMV in vitro and in vivo than commercial Ningnanmycin. Especially, tylophorine salt derivatives 10, 11, 13, 17, and 22 emerged as potential inhibitors of plant virus. These findings demonstrate that these phenanthroindolizidine alkaloids and their salt derivatives represent a new template for antiviral studies and could be considered for novel therapy against plant virus infection.

Synthesis and Antiviral Activities of Phenanthroindolizidine Alkaloids and Their Derivatives

Herein, we report a protocol for direct visible-light-mediated Minisci C–H alkylation of heteroarenes with unactivated alkyl halides using molecular oxygen as an oxidant at room temperature. This mild protocol is compatible with a wide array of sensitive functional groups and has a broad substrate scope. Notably, functionalization of (iso)quinolines, pyridines, phenanthrolines, quinazoline, and other heterocyclic compounds with unactivated primary, secondary, and tertiary alkyl halides proceeds smoothly under the standard conditions. The robustness of this protocol is further demonstrated by the late-stage functionalization of complex nitrogen-containing natural products and drugs.

Visible-light-mediated Minisci C–H alkylation of heteroarenes with unactivated alkyl halides using O2 as an oxidant

Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure–activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

Qingmin Wang

Papers

Iron(III) chloride catalyzed oxidative coupling of aromatic nuclei.

Synthesis and antiviral and fungicidal activity evaluation of β-carboline, dihydro-β-carboline, tetrahydro-β-carboline alkaloids, and their derivatives.

Synthesis and Antiviral Activities of Phenanthroindolizidine Alkaloids and Their Derivatives

Visible-light-mediated Minisci C–H alkylation of heteroarenes with unactivated alkyl halides using O2 as an oxidant

Benzoylurea Chitin Synthesis Inhibitors.