Complete Field Guide to Asymmetric BINOL-Phosphate Derived Brønsted Acid and Metal Catalysis: History and Classification by Mode of Activation; Brønsted Acidity, Hydrogen Bonding, Ion Pairing, and Metal Phosphates

The umpolung strategy encompasses all the methods that make organic molecules react in an inverse manner compared to their innate polarity-driven reactivity. This concept entered the field of organocatalysis when it was recognized that N-heterocyclic carbenes (NHCs) can provide catalytic access to acyl anion equivalents. Since then, tremendous efforts have followed to develop a broad variety of NHC-catalyzed reactions. In addition to this, more recent research developments have shown that other families of organocatalysts are also able to mediate transformations in which inversion of polarity is involved. This tutorial review aims at offering a didactic overview of organocatalytic umpolung and should serve as an inspiration for further progress in this field.

Organocatalytic umpolung: N-heterocyclic carbenes and beyond

The present review is devoted to summarizing the recent advances (2015-2017) in the field of metal-catalysed group-directed C-H functionalisation In order to clearly showcase the molecular diversity that can now be accessed by means of directed C-H functionalisation, the whole is organized following the directing groups installed on a substrate Its aim is to be a comprehensive reference work, where a specific directing group can be easily found, together with the transformations which have been carried out with it Hence, the primary format of this review is schemes accompanied with a concise explanatory text, in which the directing groups are ordered in sections according to their chemical structure The schemes feature typical substrates used, the products obtained as well as the required reaction conditions Importantly, each example is commented on with respect to the most important positive features and drawbacks, on aspects such as selectivity, substrate scope, reaction conditions, directing group removal, and greenness The targeted readership are both experts in the field of C-H functionalisation chemistry (to provide a comprehensive overview of the progress made in the last years) and, even more so, all organic chemists who want to introduce the C-H functionalisation way of thinking for a design of straightforward, efficient and step-economic synthetic routes towards molecules of interest to them Accordingly, this review should be of particular interest also for scientists from industrial R&D sector Hence, the overall goal of this review is to promote the application of C-H functionalisation reactions outside the research groups dedicated to method development and establishing it as a valuable reaction archetype in contemporary R&D, comparable to the role cross-coupling reactions play to date

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A comprehensive overview of directing groups applied in metal-catalysed C-H functionalisation chemistry.

Beijing National Laboratory of Molecular Sciences (BNLMS) and Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Green Chemistry Center, Peking University, 202 Chengfu Road, 098#, Beijing 100871, China State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 200060, China

Transition-Metal-Free Coupling Reactions

Transition-metal-catalyzed carbene transformations and cross-couplings represent two major reaction types in organometallic chemistry and organic synthesis. However, for a long period of time, these two important areas have evolved separately, with essentially no overlap or integration. Thus, an intriguing question has emerged: can cross-coupling and metal carbene transformations be merged into a single reaction cycle? Such a combination could facilitate the development of novel carbon–carbon bond-forming methodologies.Although this concept was first explored about 10 years ago, rapid developments inthis area have been achieved recently. Palladium catalysts can be used to couple diazo compounds with a wide variety of organic halides. Under oxidative coupling conditions, diazo compounds can also react with arylboronic acids and terminal alkynes. Both of these coupling reactions form carbon–carbon double bonds. As the key step in these catalytic processes, Pd carbene migratory insertion plays a vital role i...

Diazo compounds and N-tosylhydrazones: novel cross-coupling partners in transition-metal-catalyzed reactions.

In recent years, the concept of combining transition metal catalysis and organocatalysis has emerged as a promising strategy for developing new and valuable reactions, and has attracted considerable attention as it could potentially enable unprecedented transformations not currently possible by use of the transition metal complex or the organocatalyst alone. In this critical review, this strategy is illustrated with several recent outstanding examples, with the aim of shedding light on the synthetic utilities and potentials of this concept as a novel tool in organic synthesis (118 references).

Combining transition metal catalysis and organocatalysis: a broad new concept for catalysis

Transition metal-catalyzed cross-coupling reactions have been established as one of the most powerful tools for the construction of C–C and C–X bonds. In this context, the development of novel metal-catalyzed cross-coupling processes that do not require stoichiometric organometallic reagents is particularly attractive. Recently, N-tosylhydrazones have emerged as a new type of versatile coupling partners for transition metal-catalyzed cross-coupling reactions as well as metal-free cross-coupling reactions, and have attracted increasing attention. This tutorial review summarizes recent important developments in this area with N-tosylhydrazones as versatile coupling partners.

Hongbin Zhang

Papers

Combining transition metal catalysis and organocatalysis: a broad new concept for catalysis

N-Tosylhydrazones: versatile reagents for metal-catalyzed and metal-free cross-coupling reactions

Combining Transition Metal Catalysis and Organocatalysis: A Broad New Concept for Catalysis

N-Tosylhydrazones: Versatile Reagents for Metal-Catalyzed and Metal-Free Cross-Coupling Reactions