Straightforward Uranium‐Catalyzed Dehydration of Primary Amides to Nitriles

Enthaler, Stephan

doi:10.1002/chem.201101478

Cited by 62 publications

(19 citation statements)

References 48 publications

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“…Nevertheless, difficulties can arise in the presence of functional groups sensitive by side-reactions, due to the reduction abilities of the metal-hydrosilane combination. As the dehydration of primary amides is proposed to proceed via silylation we wonder if the hydrosilanes can be replaced by silylation reagents to avoid additional reduction [25,27,28]. In accordance to that we herein present the efficient application of copper precursors in combination with N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) in the dehydration of a variety of primary amides to yield the corresponding nitriles [29].…”

Section: Introductionsupporting

confidence: 62%

“…Finally, alkyl based amides were dehydrated in moderate to good yields (Table 3, entries 14 and 15). With respect to the reaction mechanism we propose a similar pathway as introduced by the groups of Nagashima for ruthenium and Beller for iron (Scheme 1) [16,[25][26][27][28]. Initially, the copper catalyst activates the primary amide by coordination of the carbonyl oxygen and provides the possibility for MSTFA to transfer the trimethylsilyl group to yield the monosilylated species 19 and N-methyltrifluoroacetamide (18).…”

Section: Resultsmentioning

confidence: 96%

“…However, the application of stoichiometric amounts of highly acidic and basic compounds disfavors the dehydration of sensitive substrate and reduces the generality of the methods. In this regard the application of transition metal catalyst turned out to be an efficient and flexible alternative and various successful procedures have been launched so far (e.g., W, Ru, Pd, Rh, V, and U) [16][17][18][19][20][21][22][23][24][25]. More recently the potential of abundant, cheap and low toxic metals (e.g., Fe, Zn) as catalysts for the dehydration of primary amides have been demonstrated [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

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Copper-Catalyzed Dehydration of Primary Amides to Nitriles

Enthaler

Weidauer

2011

Catal Lett

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In the present study we introduce a coppercatalyzed protocol for the dehydration of primary amides to their corresponding nitriles applying N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) as silylation reagent. For that purpose investigations of various reaction parameters (copper source, solvent, temperature, MSTFA and copper loading) have been carried out to find suitable reaction conditions. Simple copper(I) chloride (2.5 mol%) and MSTFA (2.0 equiv) in toluene allow for the straightforward synthesis of a variety of nitriles (15 examples).

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Section: Introductionsupporting

confidence: 62%

Section: Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Copper-Catalyzed Dehydration of Primary Amides to Nitriles

Enthaler

Weidauer

2011

Catal Lett

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“…The dehydration of primary amides to nitriles has been reported to be catalysed by only 1 mol % of uranyl nitrate, in the presence of the SiMe 3 transfer reagent N-methyl-N-(trimethylsilyl)trifluoroacetamide (Scheme 2). [35] The mechanism of this reaction is thought to occur through initial coordination of the amide to the uranyl, followed by double silylation of the primary amide and a rearrangement to eliminate (Me 3 Si) 2 O and the nitrile; the nitrile being a poorer ligand for uranyl is displaced by the incoming amide, which allows for regeneration of the catalyst. The scope of the reaction was investigated and high yields (85-99 %) of a number of aromatic and aliphatic amides realised, with a number of functional groups supported.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

New Reactivity of the Uranyl(VI) Ion

Baker

2012

Chemistry A European J

105

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The chemistry of the uranyl ion ([UO(2)](2+)) has evolved remarkably over the past few years, with unexpected reactivity observed that challenge our understanding of this ion, and of actinides in general. This review highlights some recent advances in the field, focussing on the organometallic chemistry of the uranyl moiety, which is not well developed in comparison to lower oxidation states of uranium. The use of uranyl as a catalyst is highlighted and the newly developed supramolecular chemistry is described. The uranyl oxygen atoms have been considered as inert, but recent work has shown that is not necessarily the case and is discussed herein. Finally, reduction to the [UO(2)](+) ion will be discussed.

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“…After two years, we found that dehydration of amides to nitriles could also be catalyzed by silyl hydrido iron (II) complexes in good to excellent yields . Meanwhile, it was confirmed that MSTFA as dehydration reagent is an excellent trimethylsilyl‐transfer compound . The fluoride‐catalyzed (metal‐free) dehydration of primary amides using silanes as dehydrating reagents was published by Beller's group .…”

Section: Introductionmentioning

confidence: 97%

Lewis acid promoted dehydration of amides to nitriles catalyzed by [PSiP]‐pincer iron hydrides

Chang

Zhang

et al. 2020

Applied Organom Chemis

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The dehydration of primary amides to their corresponding nitriles using four [PSiP]‐pincer hydrido iron complexes 1–4 [(2‐Ph2PC6H4)2MeSiFe(H)(PMe3)2 (1), (2‐Ph2PC6H4)2HSiFe(H)(PMe3)2 (2), (2‐(iPr)2PC6H4)2HSiFe(H)(PMe3)2 (3) and (2‐(iPr)2PC6H4)2MeSiFe(H)(PMe3)2 (4)] as catalysts in the presence of (EtO)3SiH as dehydrating reagent was explored in the good to excellent yields. It was proved for the first time that Lewis acid could significantly promote this catalytic system under milder reaction conditions than other Lewis acid‐promoted system, such as shorter reaction time or lower reaction temperature. This is also the first example that dehydration of primary amides to nitriles was catalyzed by silyl hydrido iron complexes bearing [PSiP]‐pincer ligands with Lewis acid as additive. This catalytic system has good tolerance for many substituents. Among the four iron hydrides 1 is the best catalyst. The effects of substituents of the [PSiP]‐pincer ligands on the catalytic activity of the iron hydrides were discussed. A catalytic reaction mechanism was proposed. Complex 4 is a new iron complex and was fully characterized. The molecular structure of 4 was determined by single crystal X‐ray diffraction.

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Straightforward Uranium‐Catalyzed Dehydration of Primary Amides to Nitriles

Cited by 62 publications

References 48 publications

Copper-Catalyzed Dehydration of Primary Amides to Nitriles

Copper-Catalyzed Dehydration of Primary Amides to Nitriles

New Reactivity of the Uranyl(VI) Ion

Lewis acid promoted dehydration of amides to nitriles catalyzed by [PSiP]‐pincer iron hydrides

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