Übergangsmetallkatalysierte C‐C‐Kupplungen mit Ethylen im Labormaßstab

Saini, Vaneet; Stokes, Benjamin J.; Sigman, Matthew S.

doi:10.1002/ange.201303916

Cited by 23 publications

(2 citation statements)

References 161 publications

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“…In the past decades, the simplest and abundant two‐carbon molecules, ethylene and acetylene, have been employed as C2 building blocks for the formation of small‐ and medium‐sized cyclic compounds, especially through cyclometallation reactions (Scheme a). Despite their significance, the direct incorporation of either ethylene or acetylene into cyclic compounds is still very limited because of the gas‐phase reactants. Alternatively, trihaloethenes were used as C2 building blocks in cycloaddition reactions, such as Diels–Alder reactions, [2+2] cycloadditions, and 1,3‐dipolar cycloadditions (Scheme a).…”

Section: Methodsmentioning

confidence: 99%

Acetonitrile Activation: An Effective Two‐Carbon Unit for Cyclization

Luo

Wei

et al. 2019

Angew Chem Int Ed

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A novel activation of acetonitrile for the construction of cyclobutenones by [2+2] cyclization was developed. Acetonitrile is utilized for the first time as two‐carbon (C2) cyclization building block. The present protocol successfully inhibits the competitive cycloaddition with the C≡N bond of acetonitrile, but enables the in situ formation of an unsaturated carbon–carbon bond and the subsequent cycloaddition as a C2 unit. This chemistry features simple reaction conditions, high chemoselectivities, wide substrate scope, and offers a new and practical approach to cyclobutenones and cyclobuteneimines.

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Section: Methodsmentioning

confidence: 99%

Acetonitrile Activation: An Effective Two‐Carbon Unit for Cyclization

Luo

Wei

et al. 2019

Angew Chem Int Ed

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“…B. bei Umsetzungen mit Ethen 151 oder Myrcen 152. Erwähnt sei auch noch ein aktueller Übersichtsbeitrag zur C–C‐Kupplung mit Ethen 153.…”

Section: Neue Entwicklungen In Der Hükunclassified

Neue Trends in der homogenen Übergangsmetallkatalyse

Behr

Vorholt

2014

Chemie Ingenieur Technik

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zum 80. Geburtstag gewidmet Dieser Beitrag gibt eine ausgewählte Ü bersicht über aktuelle Entwicklungen in der homogenen Ü bergangsmetallkatalyse. Im Vordergrund stehen hier vor allem technisch relevante Reaktionen, wie z. B. Hydroformylierung, Carbonylierung, Hydrierung, Oxidation, Aminierung, Metathese und resultierende Tandemreaktionen. Neben dem Einsatz klassischer petrochemischer Grundstoffe wird ebenfalls die Umsetzung nachwachsender Rohstoffe diskutiert. An ausgewählten Beispielen werden kontinuierlich durchgeführte Umsetzungen der Reaktionen in Miniplants gezeigt.This contribution presents an overview of current developments in homogeneous catalysis. In this respect, the focus lies on industrial relevant reactions like hydroformylation, carbonylation, hydrogenation, oxidation, amination and metathesis and resulting tandem reactions. Beyond the classical petrochemical feedstocks, also renewables such as a sustainable feedstock are discussed. Selected examples of homogeneous catalysis in continuously operated miniplants are given.

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Cobalt‐Catalyzed Dimerization and Homocoupling of Terminal Alkynes

Sun

Quan

et al. 2017

Asian J Org Chem

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Methods toward the dimerizationa nd homocoupling of terminal alkynesh ave been established that employ Co complexesa long with tBuOKu nder different atmosphere.Avariety of Z-1,3-enynes were furnishedw ith ah igh Z:E (up to 93:7) ratio in moderate to very good yields under inert atmosphere.Alternatively,the Glaser homocoupling reaction of terminal alkynes was also accomplished with aC oc atalyst, successfully affording various 1,3-diynes in excellent yields (up to 93 %) under oxygen.Cobalt catalysis has emerged as av ery active research area over the past decades owing to the fact that cobalt is abundant, less toxic and more biocompatible.[1] Meanwhile, the cobalt complexesw ith high affinity toward p bonds enable them to catalyze the CÀCb ond formation of terminal alkynes. As the transition-metal-catalyzed CÀCb ond formation is one of the most vital transformations in organic synthetic chemistry, [2] the reactions involvinga lkynes were investigated widely. [3][4][5] In particular,d irect dimerization [6] and Glaserh omocoupling [7] of terminal alkynes are of significant interestd ue to their atom-economy assembling av ariety of useful organic compounds, such as 1,3-diynes [8] and 1,3-enynes. [9] In addition, these products are valuable building blocks for the synthesis of polysubstituted aromatic rings, drug intermediates and natural products.I np reviousr eported works, dimerizationo ft erminal alkynes often gave E-1,3-enynes [10] and Z-1,3-enynes, [11] and only af ew examples has been reportedg iving high selectivity.A lso, to our knowledge,t he efficient Glaser homocoupling of terminal alkynes catalyzed by cobalt complexes has rarely been developed.[12]Thus, we envisionedt hat cobaltc omplexes promoted reaction of terminal alkynes would provide alternative access to 1,3-diynes and Z-selective 1,3-enynes through fine tuningo f the ligand structure. In this regard,w eh erein describe cobaltcatalyzed dimerization/homocoupling of terminala lkynes in the presence of tBuOK, depending on the cobalt complexes and reaction conditions. Notably,o nly dimer 1,3-enynes were obtained in the presence of pincer-CoCl 2 complex with ap roline based tridentate nitrogen ligand under inert atmosphere (Scheme 1). The homocoupling product 1,3-diynesw erea lso furnished under oxidative atmosphere.Initially,w ec arriedo ut the dimerization reactiono fp henylacetylene with 1.0 mol %d ifferentC oc omplexes ( Figure 1) in the presence of tBuOK at 80 8CinPhCl under inert atmosphere. To our delight, the dimerization of terminal alkyne proceeded successfully and provided 1,3-enyne by cobalt complex C1 with good yields. Further,t he Co complex C2 with proline derived tridentate nitrogen ligand delivered the dimerization with ah igh Z:E ratio (Table 1, entry 2; 89:11).[13] Not surprisingly,t he use of CoCl 2 as catalyst only led to poor result (entry 4), and the ligand could not promote the dimerization of alkyne separately (entry 5). Then, different anions of Co complexes were examined. When the complexw as prepared using Co(OT...

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Übergangsmetallkatalysierte C‐C‐Kupplungen mit Ethylen im Labormaßstab

Cited by 23 publications

References 161 publications

Acetonitrile Activation: An Effective Two‐Carbon Unit for Cyclization

Acetonitrile Activation: An Effective Two‐Carbon Unit for Cyclization

Neue Trends in der homogenen Übergangsmetallkatalyse

Cobalt‐Catalyzed Dimerization and Homocoupling of Terminal Alkynes

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