Remote functionalization through alkene isomerization
TL;DR: The aim is to demonstrate that using a double bond as a chemical handle, metal-assisted long-distance activation could be used as a powerful synthetic strategy, leading to a selective reaction at a position distal to the initial double bond.
Abstract: Exploiting the reactivity of one functional group within a molecule to generate a reaction at a different position is an ongoing challenge in organic synthesis. Effective remote functionalization protocols have the potential to provide access to almost any derivatives but are difficult to achieve. The difficulty is more pronounced for acyclic systems where flexible alkyl chains are present between the initiating functional group and the desired reactive centres. In this Review, we discuss the concept of remote functionalization of alkenes using metal complexes, leading to a selective reaction at a position distal to the initial double bond. We aim to show the vast opportunity provided by this growing field through selected and representative examples. Our aim is to demonstrate that using a double bond as a chemical handle, metal-assisted long-distance activation could be used as a powerful synthetic strategy.
Citations
More filters
TL;DR: A comprehensive overview on first row transition metal catalysts for C-H activation until summer 2018 is provided.
Abstract: 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.
1,417 citations
01 May 2018
TL;DR: Recently, some alternative design strategies have emerged that afforded new classes of olefin polymerization catalysts as mentioned in this paper, and they enable novel reactivity patterns they enable, which is a major driving force in polyolefin studies.
Abstract: More than 50 years have passed since Ziegler and Natta shared the Nobel Prize in Chemistry for their discovery of olefin polymerization catalysts. The field of metal-catalysed polymerization has since matured, in no small part owing to the development of several high-performance catalysts. Although polymerization research has in many ways been driven by catalyst development, this has often occurred as a result of trial and error discovery of a promising motif, followed by extensive tuning of the steric and electronic properties of the ligand(s) present in the lead complex. Recently, some alternative design strategies have emerged that afforded new classes of olefin polymerization catalysts. This Perspective highlights recently designed catalyst motifs and the novel reactivity patterns they enable. Special attention is given to methods specifically designed for the copolymerization of ethylene with polar-functionalized co-monomers — challenging reactions that showcase these creatively designed catalyst motifs. The development of high-performance olefin polymerization catalysts is a major driving force in polyolefin studies. This Perspective discusses some alternative strategies for catalyst design — strategies in which existing systems are tuned beyond merely modifying the electronic and steric properties.
384 citations
TL;DR: This work describes a catalytic method that is capable of promoting carboxylation reactions at remote and unfunctionalized aliphatic sites with carbon dioxide at atmospheric pressure and demonstrates that site-selectivity can be switched and controlled, enabling the functionalization of less-reactive positions in the presence of a priori more reactive ones.
Abstract: Catalytic carbon-carbon bond formation has enabled the streamlining of synthetic routes when assembling complex molecules. It is particularly important when incorporating saturated hydrocarbons, which are common motifs in petrochemicals and biologically relevant molecules. However, cross-coupling methods that involve alkyl electrophiles result in catalytic bond formation only at specific and previously functionalized sites. Here we describe a catalytic method that is capable of promoting carboxylation reactions at remote and unfunctionalized aliphatic sites with carbon dioxide at atmospheric pressure. The reaction occurs via selective migration of the catalyst along the hydrocarbon side-chain with excellent regio- and chemoselectivity, representing a remarkable reactivity relay when compared with classical cross-coupling reactions. Our results demonstrate that site-selectivity can be switched and controlled, enabling the functionalization of less-reactive positions in the presence of a priori more reactive ones. Furthermore, we show that raw materials obtained in bulk from petroleum processing, such as alkanes and unrefined mixtures of olefins, can be used as substrates. This offers an opportunity to integrate a catalytic platform en route to valuable fatty acids by transforming petroleum-derived feedstocks directly.
328 citations
TL;DR: This Perspective highlights the recent advances in visible light-mediated generation of amidyl, hydrazonyl, and imidyl radicals from a variety of precursors.
Abstract: During the past decade, visible light photocatalysis has become a powerful synthetic platform for promoting challenging bond constructions under mild reaction conditions. These photocatalytic systems rely on harnessing visible light energy for synthetic purposes through the generation of reactive but controllable free radical species. Recent progress in the area of visible light photocatalysis has established it as an enabling catalytic strategy for the mild and selective generation of nitrogen-centered radicals. The application of visible light for photocatalytic activation of amides, hydrazones, and imides represents a valuable approach for facilitating the formation of nitrogen-centered radicals. Within the span of only a couple of years, significant progress has been made for expediting the generation of amidyl, hydrazonyl, and imidyl radicals from a variety of precursors. This Perspective highlights the recent advances in visible light-mediated generation of these radicals. A particular emphasis is p...
286 citations
TL;DR: This work reviews homogeneous cobalt-catalyzed hydride transfer reactions according to the classified reaction types and provides a comprehensive overview of the design, synthesis, and reactivity of cobalt catalysts, their catalytic applications, and reaction mechanisms.
Abstract: Cobalt has become increasingly attractive in homogeneous catalysis because of its unique characteristics and outstanding catalytic performance in addition to being cheap and earth-abundant. Hydride transfer processes are involved in a broad range of organic transformations that allow the facile preparation of various useful chemicals and synthetic building blocks. These reactions have continuously received great attention both from academia and industry. In this perspective, we review homogeneous cobalt-catalyzed hydride transfer reactions according to the classified reaction types and provide a comprehensive overview of the design, synthesis, and reactivity of cobalt catalysts, their catalytic applications, and reaction mechanisms.
260 citations
References
More filters
4,919 citations
2,770 citations
Book•
01 Jan 1988
TL;DR: General Properties of Organometallic Complexes The Metal-Carbon and Metal-Hydrogen Bonds Ligand Substitution Reactions Complexes of Pi-Bound Ligands Oxidative Addition and Reductive Elimination Insertion and Elimination Nucleophilic and Electrophilic Additions and Abstraction Homogeneous Catalysis Characterization of OO Compounds Carbenes, Metathesis and Polymerization The Activation of Small Molecules Clusters and the Metal-Metal Bond Applications to Organic Synthesis Oxidation and High-Oxidation-State
Abstract: General Properties of Organometallic Complexes The Metal-Carbon and Metal-Hydrogen Bonds Ligand Substitution Reactions Complexes of Pi-Bound Ligands Oxidative Addition and Reductive Elimination Insertion and Elimination Nucleophilic and Electrophilic Addition and Abstraction Homogeneous Catalysis Characterization of Organometallic Compounds Carbenes, Metathesis and Polymerization The Activation of Small Molecules Clusters and the Metal-Metal Bond Applications to Organic Synthesis Oxidation and High-Oxidation-State Complexes Bioorganometallic Chemistry Solutions to Problems.
1,651 citations