C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material sciences, crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these C–H functionalizations required precious 4d or 5d transition metal catalysts. Given the cost-effective and sustainable nature of earth-abundant first row transition metals, the development of less toxic, inexpensive 3d metal catalysts for C–H activation has gained considerable recent momentum as a significantly more environmentally-benign and economically-attractive alternative. Herein, we provide a comprehensive overview on first row transition metal catalysts for C–H activation until summer 2018.

3d Transition Metals for C-H Activation.

CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

Metal-catalyzed enantioselective allylation, which involves the substitution of allylic metal intermediates with a diverse range of different nucleophiles or S(N)2'-type allylic substitution, leads to the formation of C-H, -C, -O, -N, -S, and other bonds with very high levels of asymmetric induction. The reaction may tolerate a broad range of functional groups and has been applied successfully to the synthesis of many natural products and new chiral compounds.

Metal-catalyzed enantioselective allylation in asymmetric synthesis.

A review. Transition metal catalyzed decarboxylative allylations, benzylations, and interceptive allylations are reviewed.

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Transition Metal-Catalyzed Decarboxylative Allylation and Benzylation Reactions

Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C–C single bond or C═C double bond formations in transition-metal-catalyzed reactions. This type of coupling reaction involves the following general steps. First, the organometallic species is generated by various processes, including oxidative addition, transmetalation, cyclization, C–C bond cleavage, and C–H bond activation. Subsequently, the organometallic species reacts with the diazo substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion to form a C–C bond. The new organometallic species generated from migratory insertion may undergo various transformations. This type of carbene-based coupling has proven...

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Conventional organic synthesis has been mainly based upon the reactivities of π-bonds and polar σ-bonds. Carbon–carbon single bonds are nonpolar and generally far less reactive. Although they remain intact under most reaction conditions, it is possible to activate and cleave them if suitable organometallic compounds or metal catalysts are applied. Such C–C single bond cleavage reactions are attracting increasing attention in the context of synthetic chemistry because they provide a unique and more straightforward route from readily available substances to targets, while requiring significantly fewer steps. The present Perspective aims to exemplify the potential of metal-catalyzed C–C single bond cleavage for organic synthesis.

Potential of Metal-Catalyzed C–C Single Bond Cleavage for Organic Synthesis

o-Alkylphenyl ketones undergo a C-C bond forming carboxylation reaction with CO2 simply upon irradiation with UV light or even solar light. The reaction presents a clean process exploiting light energy as the driving force for carboxylation of organic molecules with CO2.

Light-Driven Carboxylation of o-Alkylphenyl Ketones with CO2

The title reaction occurs through the use of not only pyridine, but also quinoline and pyrimidine as the directing groups.

Pyridine‐Directed Palladium‐Catalyzed Phosphonation of C(sp2) ? H Bonds

Pyridine−borane complexes were synthesized from 2-arylpyridines through an electrophilic aromatic borylation reaction with BBr3. The intermediate 2-(2-dibromoborylaryl)pyridines were stable enough to be handled in air and served as the synthetic platform for variously substituted pyridine−borane complexes. This facile method would be useful for the synthesis of aza-π-conjugated materials having boron−nitrogen coordination.

Synthesis of Pyridine−Borane Complexes via Electrophilic Aromatic Borylation

This article reviews synthetic transformations involving cleavage of a carbon–carbon bond of a four-membered ring, with a particular focus on the examples reported during the period from 2011 to th...

Naoki Ishida

Papers

Potential of Metal-Catalyzed C–C Single Bond Cleavage for Organic Synthesis

Light-Driven Carboxylation of o-Alkylphenyl Ketones with CO2

Pyridine‐Directed Palladium‐Catalyzed Phosphonation of C(sp2) ? H Bonds

Synthesis of Pyridine−Borane Complexes via Electrophilic Aromatic Borylation

Cleavage of Carbon-Carbon σ-Bonds of Four-Membered Rings.