Eine effiziente und allgemein anwendbare Fe‐katalysierte Arylierung von Benzylalkoholen und Benzylcarboxylaten

Iovel, I.; Mertins, Kristin; Kischel, Jette; Zapf, Alexander; Beller, Matthias

doi:10.1002/ange.200462522

Cited by 120 publications

(38 citation statements)

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“…Thus any alternative and potentially milder method not dependent on Brønstedt acids must use water-tolerant Lewis acids. Since in the first step benzyl alcohols 3 are produced, the second step in which the latter reacts with a second molecule of the electron-rich arene is closely related to an iron-catalyzed reaction reported by Beller et al [3] this year. Other activated alcohols recently shown to undergo similar reactions are propargylic alcohols, here Uemura et al [4] investigated ruthenium catalysts and Toste et al [5] rhenium catalysts.…”

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confidence: 87%

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The Condensation of Carbonyl Compounds with Electron-Rich Arenes: Mercury, Thallium, Gold or a Proton?

et al. 2006

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Gold(III) chloride, mercury(II) perchlorate, thallium(III) perchlorate and p-toluenesulfonic acid were found to efficiently catalyze the condensation of two furans with aldehydes or acetone. The olefinic unit of a,b-unsaturated carbonyl compounds reacts faster than the carbonyl group, other olefins do not react selectively. The first (addition) step is rate-limiting, the second (substitution) step is much faster.

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confidence: 87%

“…Another Lewis acid, known to be water-tolerant, is Yb(OTf) 3 . With the same amount of this catalyst after 2 days only 5% conversion to 7 were observed.…”

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confidence: 99%

The Condensation of Carbonyl Compounds with Electron-Rich Arenes: Mercury, Thallium, Gold or a Proton?

et al. 2006

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“…Remarkable are the Ru-, [3] Re-, [4] and Au-catalyzed [5] propargylation of nucleophiles with propargylic alcohols, the Tsuji-Trost reaction of allylic alcohols with active methylene compounds, [6] the reaction of secondary benzylic alcohols with different nucleophiles catalyzed by La, Sc, or Hf salts, [7] and the Fe-, or Au-catalyzed arylation of benzylic alcohols. [8] In addition, InCl 3 has emerged as a powerful catalyst to perform direct nucleophilic substitution of allylic and benzylic alcohols. [9] Although the catalytic activation of alcohols is thought to be difficult due to the poor leaving ability of the OH group, we have recently found that simple Brønsted acids like p-toluenesulfonic acid monohydrate (PTS) catalyze the direct nucleophilic substitution of propargylic alcohols.…”

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Brønsted Acid‐Catalyzed Nucleophilic Substitution of Alcohols

et al. 2006

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Abstract:Simple Brønsted acids such as p-toluenesulfonic acid monohydrate (PTS) or polymer-bound p-toluenesulfonic acid efficiently catalyze the direct nucleophilic substitution of the hydroxy group of allylic and benzylic alcohols with a large variety of carbon-and heteroatom-centered nucleophiles. Reaction conditions are mild, the process is conducted under an atmosphere of air without the need for dried solvents, and water is the only side product of the reaction.Keywords: alcohols; C À C coupling; nucleophilic substitution; supported catalysts; synthetic methodsThe construction of C À C bonds is a fundamental reaction in organic synthesis and coupling reactions between reactive nucleophiles (NuH) and halides (RX) or related species are one of the most used strategies. In this context, direct substitution of the hydroxy group in alcohols by nucleophiles could be considered as an ideal process because of the wide availability of the starting materials and the generation of H 2 O as the only side product. However, the main limitation of this strategy is that an excess of sulfuric acid, polyphosphoric acid, [1] or a stoichiometric amount of a Lewis acid [2] is required, and so the range of possible nucleophiles is limited. Therefore, the development of catalytic versions of this reaction remains as a major objective of the modern organic chemistry (Scheme 1). Recent advances in this field are based on the use of transition metal complexes as catalysts. Remarkable are the Ru-, [3] Re-, [4] and Au-catalyzed [5] propargylation of nucleophiles with propargylic alcohols, the Tsuji-Trost reaction of allylic alcohols with active methylene compounds, [6] the reaction of secondary benzylic alcohols with different nucleophiles catalyzed by La, Sc, or Hf salts, [7] and the Fe-, or Au-catalyzed arylation of benzylic alcohols.[8] In addition, InCl 3 has emerged as a powerful catalyst to perform direct nucleophilic substitution of allylic and benzylic alcohols. [9] Although the catalytic activation of alcohols is thought to be difficult due to the poor leaving ability of the OH group, we have recently found that simple Brønsted acids like p-toluenesulfonic acid monohydrate (PTS) catalyze the direct nucleophilic substitution of propargylic alcohols.[10] Herein we report a strategy involving simple Brønsted acid-catalyzed activation of allylic and benzylic alcohols as a method for the direct formation of new C À C and C À heteroatom bonds from carbon (active methylene compounds, aromatic and heteroaromatic compounds), nitrogen, sulfur, and oxygen nucleophiles and alcohols. Surprisingly, the Brønsted acid-catalyzed direct substitution of allylic alcohols has not been reported in the literature and so no systematic study has so far been performed. Moreover, in some recent papers this reaction has been reported not to proceed at all. [9b] Despite all these negative forewarnings, we decided to investigate the reaction of allylic alcohol 1a as a model substrate with selected nucleophiles 2-8 under PTS-catalyzed conditions (Sche...

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“…[28][29][30] The application of inexpensive, non-toxic, commercially available, and environmentally benign iron complexes as catalysts in chemical syntheses has attracted much attention. [31,32] Recently, iron has been utilized extensively as a catalyst to promote the "traditional" cross-coupling between R 1 X and R 2 M. [33][34][35][36][37][38][39][40][41] Iron catalysts are also involved in many important transformations, such as Friedel-Crafts benzylation, [42,43] carbonylation, [44] oxidation [45,46] and other processes. [47][48][49][50][51][52][53][54] Of great interest are the recently developed oxidative coupling reactions of Ar 1 M with Ar 2 H to generate Ar products by employing Fe complexes as the catalysts.…”

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confidence: 99%