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

/pdf/a-comprehensive-overview-of-directing-groups-applied-in-543u6d0g60.pdf

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

Good Partnership between Sulfur and Fluorine: Sulfur-Based Fluorination and Fluoroalkylation Reagents for Organic Synthesis

Alkylation reactions represent an important organic transformation to form C–C bonds. In addition to conventional approaches with alkyl halides or sulfonates as alkylating agents, the use of unactivated olefins for alkylations has become attractive from both cost and sustainability viewpoints. This Review summarizes transition-metal-catalyzed alkylations of various carbon–hydrogen bonds (addition of C–H bonds across olefins) using regular olefins or 1,3-dienes up to May 2016. According to the mode of activation, the Review is divided into two sections: alkylation via C–H activation and alkylation via olefin activation.

Transition-Metal-Catalyzed C–H Alkylation Using Alkenes

Selective cleavages of carbon-carbon bonds catalyzed by transition-metal complexes have been shown to be increasingly versatile tools for organic synthesis allowing for complementary synthetic strategies Numerous examples of transition-metal catalyzed C-C bond activations of three- and four-membered ring systems have been reported These strained rings have been shown to engage in a variety of new ring-opening rearrangements and cycloaddition reactions leading to valuable structures Besides strain-driven transformations, other facilitating strategies to enforce the C-C bond activation of unstrained molecules have been developed as well While the variety of different transformations is less abundant, they concentrate on chelation-assisted reactions using appropriate permanent or transient directing groups In particular, the cleavage and subsequent functionalization of the C-CN bonds and decarbonylation processes operating by an excision of carbon monoxide from ketone derivatives have witnessed a large progress

Catalytic C-C Bond Activations via Oxidative Addition to Transition Metals.

Recent Advances in Transition-Metal-Catalyzed Functionalization of Unstrained Carbon–Carbon Bonds

Mechanistic Manifold and New Developments of the Julia–Kocienski Reaction

The functionalization of carbon-hydrogen bonds in non-nucleophilic substrates using α-carbonyl sulfoxonium ylides has not been so far investigated, despite the potential safety advantages that those reagents would provide over diazo compounds or their in situ precursors. We describe the cross-coupling reactions of sulfoxonium ylides with C(sp2)-H bond of arenes and heteroarenes in the presence of a rhodium catalyst. The reaction proceeds by a succession of C-H activation, migratory insertion of the ylide into the carbon-metal bond and protonation, the last step being turnover-limiting. The method is applied to the synthesis of benz[c]acridines when allied to an iridium-catalyzed dehydrative cyclization.

/pdf/cross-coupling-of-a-carbonyl-sulfoxonium-ylides-with-c-h-36oyys6uep.pdf

Cross-Coupling of α-Carbonyl Sulfoxonium Ylides with C-H Bonds.

Transition-Metal-CatalyzedRearrangements of Small Cycloalkanes: RegioselectivityTrends in β-Carbon Elimination Reactions

Transition-metal-catalyzed activation of otherwise inert C H and C C bonds is widely recognized as a very promising strategy for the development of sustainable synthetic chemistry. 2] In this context, b-carbon elimination of putative pentarhodacycles, having an exocyclic C=O double bond, has been used in the design of reactions to promote the ring enlargement of non-functionalized cyclobutanes into larger rings [Eqs. (1) and (2)]. Both approaches relied on the insertion of rhodium catalysts into particularly strained cyclobutenones and cyclobutanones, respectively. In contrast, we now disclose the outcome of an alternative strategy which relies on stable aldehydes as precursors in a C H/C C activation sequence (Scheme 1).

Combined Rhodium‐Catalyzed Carbon–Hydrogen Activation and β‐Carbon Elimination to access Eight‐Membered Rings

The scope of the methylenation of aldehydes and ketones under optimized Julia−Kocienski conditions is broadened by using 1-tert-butyl-1H-tetrazol-5-ylmethyl sulfone Two different Barbier-type procedures are applied with NaHMDS at −78 °C or Cs2CO3 at 70 °C The latter conditions are also adapted for the preparation of 1,2-disubstituted olefins and intramolecular olefination reactions

Christophe Aïssa

Papers

Mechanistic Manifold and New Developments of the Julia–Kocienski Reaction

Cross-Coupling of α-Carbonyl Sulfoxonium Ylides with C-H Bonds.

Transition-Metal-CatalyzedRearrangements of Small Cycloalkanes: RegioselectivityTrends in β-Carbon Elimination Reactions

Combined Rhodium‐Catalyzed Carbon–Hydrogen Activation and β‐Carbon Elimination to access Eight‐Membered Rings

Improved Julia-Kocienski conditions for the methylenation of aldehydes and ketones.