Amide‐Directed C−H Sodiation by a Sodium Hydride/Iodide Composite

Huang, Yinhua; Chan, Guo Hao; Chiba, Shunsuke

doi:10.1002/ange.201702512

Cited by 21 publications

(9 citation statements)

References 45 publications

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“…Despite the recent progress, there is still ample room to develop methods for reducing simple amides into aldehydes, that can be conducted in operationally simple and cost‐effective manners under milder reaction conditions. We recently disclosed that sodium hydride (NaH) could act as a hydride donor in the presence of NaI or LiI in THF, capable of performing a series of unprecedented hydride reduction such as hydrodecyanation of carbonitriles ( Scheme ,a ), hydrodehalogenation of haloarenes ( Scheme ,b ), and dearylation of arylphosphine oxides ( Scheme ,c ) . In this context, we envisioned that use of the sodium hydride–iodide composite for the reduction of amides results in unique outcomes .…”

Section: Introductionmentioning

confidence: 99%

Reduction of N,N‐Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite

Chan

Ong

Yen

et al. 2018

Helvetica Chimica Acta

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A new and concise protocol for selective reduction of N,N‐dimethylamides into aldehydes was established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH‐NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N‐dimethylamides with wide substituent compatibility. Retention of α‐chirality in the reduction of α‐enantioriched amides was accomplished. Use of sodium deuteride (NaD) offers a new step‐economical alternative to prepare deuterated aldehydes with high deuterium incorporation rate. The NaH‐NaI composite exhibits unique chemoselectivity for reduction of N,N‐dimethylamides over ketones.

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Section: Introductionmentioning

confidence: 99%

Reduction of N,N‐Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite

Chan

Ong

Yen

et al. 2018

Helvetica Chimica Acta

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“…Organosodium chemistry has long been overshadowed by wellestablished organolithium chemistry. Alhough there has been some recent renewed interest in the use of organosodium compounds for organic synthesis [46][47][48][49][50][51][52][53][54][55][56][57][58] , the lack of general and reliable preparation methods has hindered the development of truly useful reactions. To change this status quo, we have demonstrated in this paper that efficient halogen-sodium exchange reactions are now possible~80 years after the seminal study 14 , using neopentylsodium as a key metalating reagent, to expand the repertoire of available organosodium compounds greatly 59 .…”

Section: Discussionmentioning

confidence: 99%

Halogen–sodium exchange enables efficient access to organosodium compounds

et al. 2021

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With sodium being the most abundant alkali metal on Earth, organosodium compounds are an attractive choice for sustainable chemical synthesis. However, organosodium compounds are rarely used—and are overshadowed by organolithium compounds—because of a lack of convenient and efficient preparation methods. Here we report a halogen–sodium exchange method to prepare a large variety of (hetero)aryl- and alkenylsodium compounds including tri- and tetrasodioarenes, many of them previously inaccessible by other methods. The key discovery is the use of a primary and bulky alkylsodium lacking β-hydrogens, which retards undesired reactions, such as Wurtz–Fittig coupling and β-hydrogen elimination, and enables efficient halogen–sodium exchange. The alkylsodium is readily prepared in situ from neopentyl chloride and an easy-to-handle sodium dispersion. We believe that the efficiency, generality, and convenience of the present method will contribute to the widespread use of organosodium in organic synthesis, ultimately contributing to the development of sustainable organic synthesis by rivalling the currently dominant organolithium reagents.

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“…On the other hand, our group recently disclosed that sodium hydride (NaH) could act as a hydride donor in the presence of NaI or LiI in THF, capable of performing controlled reduction of tertiary carboxamides into aldehydes ( Scheme ) . This unique controlled feature could be observed even if the reactions are performed at higher reaction temperature ( i. e ., reflux in THF), implying that the resulting anionic carbinol amine intermediate II is kept extremely stable under the reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Insights on Reduction of Carboxamides by Diisobutylaluminum Hydride and Sodium Hydride−Iodide Composite

Ong

Watanabe

Takita

et al. 2019

Helvetica Chimica Acta

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Dedicated to Professor Philippe Renaud in celebration of his 60th birthdayThe reaction mechanisms on reduction of tertiary carboxamides by diisobutylaluminum hydride (DIBAL) and sodium hydride (NaH)-sodium iodide (NaI) composite were elucidated by the computational and experimental approaches. Reduction of N,N-dimethyl carboxamides with DIBAL provides the corresponding amines, whereas that with the NaHÀ NaI composite exclusively forms aldehyde even at high reaction temperature. DFT calculations revealed that dimeric structural nature of DIBAL and Lewis acidity on its Al center play crucial role to decompose the tetrahedral anionic carbinol amine intermediate through CÀ O bond cleavage. On the other hand, in the reduction with the NaHÀ NaI composite, the resulting tetrahedral anionic carbinol amine intermediate could be kept stable, thus providing aldehydes as a sole product by the aqueous workup Scheme 2. Controlled reduction of amides into aldehydes by NaHÀ NaI. Scheme 3. Reduction of amide 1a. Scheme 4. Reduction of amide 1b.[a] The reactions were conducted using 0.5 mmol of amide 1a.[b] 1 H-NMR yields based on the internal standard.

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Amide‐Directed C−H Sodiation by a Sodium Hydride/Iodide Composite

Cited by 21 publications

References 45 publications

Reduction of N,N‐Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite

Reduction of N,N‐Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite

Halogen–sodium exchange enables efficient access to organosodium compounds

Mechanistic Insights on Reduction of Carboxamides by Diisobutylaluminum Hydride and Sodium Hydride−Iodide Composite

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