Iridium‐Catalyzed Formyl‐Selective Deuteration of Aldehydes

Kerr, William J.; Reid, Marc; Tuttle, Tell

doi:10.1002/ange.201702997

Cited by 23 publications

(5 citation statements)

References 46 publications

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“…Accordingly, gem ‐diboryl compound 60 and secondary alkylboronic ester 63 were obtained. In addition, convertion of aldehyde 56 to deuterated olefinic functionality 61 was conducted to show the value of the deuterated aldehyde [27] . gem ‐Dibromoolefins can be used as key precursors to confer molecular complexity, and aldehyde 2 served as the precursor for gem ‐dibromoolefin 64 [28] .…”

Section: Resultsmentioning

confidence: 99%

Triflylpyridinium Enables Rapid and Scalable Controlled Reduction of Carboxylic Acids to Aldehydes using Pinacolborane

et al. 2022

Angewandte Chemie

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Building up new and efficient methods for the controlled conversion of carboxylic acids to aldehydes is important. Herein, we report a rapid, modular and scalable method for the conversion of carboxylic acids to aldehydes using pinacolborane at ambient temperature, in which a triflylpyridinium reagent is used. The conversion of carboxylic acid to intermediate acylpyridinium by triflylpyridinium is new. A binary pyridinecoordinated boronium complex is generated after reduction. The unprecedented reduction of the acylpyridinium by HBpin opens up a practically direct synthesis of aldehydes from carboxylic acids. Theoretical studies indicate that the reduction of acylpyridinium requires a lower activation free energy than that of the product aldehyde. The synthetic advantage of this protocol is further highlighted by the scalable synthesis of aldehyde via continuous flow process. Configuration retention for chiral acids are presented in those syntheses.

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Section: Resultsmentioning

confidence: 99%

Triflylpyridinium Enables Rapid and Scalable Controlled Reduction of Carboxylic Acids to Aldehydes using Pinacolborane

et al. 2022

Angewandte Chemie

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“…Interestingly, only the C-1 proton was selectively exchanged (no traces of side-labelling was detected in the aromatic parts even using a 92.1 MHz 2 H-{ 1 H} NMR spectrometer equipped with a 2 H cryogenic probe) in contrast with the recently described method using an homogeneous Ir catalyst. [14] Electron-poor 4-acetamidobenzaldehyde 20 was also labelled with a good deuterium uptake and with limited reduced side-product. For 4-Dimethylaminobenzaldehyde 21 only the C-1 proton was exchanged using the NHC-modified catalyst while the use of the native Ru/C has led to sideposition labellings and the formation of high amount of side products.…”

Section: Zuschriftenmentioning

confidence: 99%

Tuning the Reactivity of a Heterogeneous Catalyst using N‐Heterocyclic Carbene Ligands for C−H Activation Reactions

et al. 2020

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We report the dramatic impact of the addition of N‐heterocyclic carbenes (NHCs) on the reactivity and selectivity of heterogeneous Ru catalysts in the context of C−H activation reactions. Using a simple and robust method, we prepared a series of new air‐stable catalysts starting from commercially available Ru on carbon (Ru/C) and differently substituted NHCs. Associated with C−H deuteration processes, depending on Ru/C‐NHC ratios, the chemical outcome can be controlled to a large extent. Indeed, tuning the reactivity of the Ru catalyst with NHC enabled: 1) increased chemoselectivity and the regioselectivity for the deuteration of alcohols in organic media; 2) the synthesis of fragile pharmaceutically relevant deuterated heterocycles (azine, purine) that are otherwise completely reduced using unmodified commercial catalysts; 3) the discovery of a novel reactivity for such heterogeneous Ru catalysts, namely the selective C‐1 deuteration of aldehydes.

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“…[27][28][29] Recently, Kerr and co-workers reported a selective deuteration of aromatic aldehydes (Figure 1C), which involves the activation of formyl C-H bonds by an iridium catalyst and isotope exchange with D 2 . 30 Newman and coworkers developed a ruthenium-catalyzed formyl H/D exchange reaction of aromatic aldehydes with D 2 O able to achieve up to 84% deuteration (Figure 1C). 31 Nevertheless, these H/D exchange reactions still rely on noble-metal catalysts, and their substrate scope remains mostly limited to aromatic aldehydes.…”

Section: Interrupted Benzoin Condensation In Deuterated Methanolmentioning

confidence: 99%