ChemInform Abstract: Hydroacylation of 1‐Alkene with 2‐(Diphenylphosphino)benzaldehyde by Rh(I).

Lee, H.; Jun, Chul Ho

doi:10.1002/chin.199532067

Cited by 6 publications

(9 citation statements)

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“…Subsequently, we turned our attention to the possible transformations of the coupling partners including different chelating atoms and observed that the vicinal S-chelation of the aldehyde could also facilitate this regioselective formal hydroacylation, albeit in an inferior yield ( 3qa ). The reaction of quinoline-8-carbaldehyde 1r , was unsuccessful presumably due to the electron-withdrawing nature of the nitrogen atom of pyridine moiety, and the weak chelation performance of a phosphine group might account for the unproductive conversion of the substrate ( 1s ). The conversion of 2-aminobenzaldehyde 1t led to a complex mixture, although the desired ester could be detected by 1 H NMR analysis.…”

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confidence: 99%

Rhodium-Catalyzed Regioselective Formal Hydroacylation of Vinyl Epoxides toward Esters Involving β-Carbon Cleavage

et al. 2021

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Herein we disclose the first example of the formal hydroacylation reactions of vinyl epoxides with chelating aldehydes enabled by rhodium catalysis for the efficient construction of functionalized esters. Detailed investigations of the mechanistic pathway reveal that the presence of a 2-vinyl group is essential in contributing to the success of this regioselective reaction, which might proceed through β-carbon cleavage as the key procedure.

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confidence: 99%

Rhodium-Catalyzed Regioselective Formal Hydroacylation of Vinyl Epoxides toward Esters Involving β-Carbon Cleavage

et al. 2021

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“…10 Next, Jun and co-workers discovered that 2-(diphenylphosphino)benzaldehyde couples to a range of olefins. 11 Miura and Willis expanded the scope of the aldehyde partner to include proximal coordinating groups, such as alcohols, sulfides, and amines. 12 An alternative strategy uses catalytic scaffolding groups to achieve similar levels of reactivity and selectivity.…”

Section: Aldehyde C−h Bond Functionalizationmentioning

confidence: 99%

“…Following initial reports of intramolecular olefin hydroacylation, Suggs showed that quinoline aldehydes do not undergo decarbonylation but, instead, couple to olefins by intermolecular hydroacylation . Next, Jun and co-workers discovered that 2-(diphenylphosphino)benzaldehyde couples to a range of olefins . Miura and Willis expanded the scope of the aldehyde partner to include proximal coordinating groups, such as alcohols, sulfides, and amines .…”

Section: Aldehyde C–h Bond Functionalizationmentioning

confidence: 99%

Teaching Aldehydes New Tricks Using Rhodium- and Cobalt-Hydride Catalysis

2021

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Conspectus By using transition metal catalysts, chemists have altered the “logic of chemical synthesis” by enabling the functionalization of carbon–hydrogen bonds, which have traditionally been considered inert. Within this framework, our laboratory has been fascinated by the potential for aldehyde C–H bond activation. Our approach focused on generating acyl-metal-hydrides by oxidative addition of the formyl C–H bond, which is an elementary step first validated by Tsuji in 1965. In this Account, we review our efforts to overcome limitations in hydroacylation. Initial studies resulted in new variants of hydroacylation and ultimately spurred the development of related transformations (e.g., carboacylation, cycloisomerization, and transfer hydroformylation). Sakai and co-workers demonstrated the first hydroacylation of olefins when they reported that 4-pentenals cyclized to cyclopentanones, using stoichiometric amounts of Wilkinson’s catalyst. This discovery sparked significant interest in hydroacylation, especially for the enantioselective and catalytic construction of cyclopentanones. Our research focused on expanding the asymmetric variants to access medium-sized rings (e.g., seven- and eight-membered rings). In addition, we achieved selective intermolecular couplings by incorporating directing groups onto the olefin partner. Along the way, we identified Rh and Co catalysts that transform dienyl aldehydes into a variety of unique carbocycles, such as cyclopentanones, bicyclic ketones, cyclohexenyl aldehydes, and cyclobutanones. Building on the insights gained from olefin hydroacylation, we demonstrated the first highly enantioselective hydroacylation of carbonyls. For example, we demonstrated that ketoaldehydes can cyclize to form lactones with high regio- and enantioselectivity. Following these reports, we reported the first intermolecular example that occurs with high stereocontrol. Ketoamides undergo intermolecular carbonyl hydroacylation to furnish α-acyloxyamides that contain a depsipeptide linkage. Finally, we describe how the key acyl-metal-hydride species can be diverted to achieve a C–C bond-cleaving process. Transfer hydroformylation enables the preparation of olefins from aldehydes by a dehomologation mechanism. Release of ring strain in the olefin acceptor offers a driving force for the isodesmic transfer of CO and H2. Mechanistic studies suggest that the counterion serves as a proton-shuttle to enable transfer hydroformylation. Collectively, our studies showcase how transition metal catalysis can transform a common functional group, in this case aldehydes, into structurally distinct motifs. Fine-tuning the coordination sphere of an acyl-metal-hydride species can promote C–C and C–O bond-forming reactions, as well as C–C bond-cleaving processes.

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“…Hydroacylation (HA) is a C–C bond forming reaction between an aldehyde and an alkyne or alkene to form an enone or ketone, respectively (Scheme A), via an atom efficient, sequential, C–H activation and C–C coupling. , The development of intermolecular hydroacylation is particularly attractive, due to the availability of an enormous variety of potential coupling partners. Although significant focus has been placed upon methodologies using nontethered aldehydes, promoted by Ru, − Ni, , Co, , and Rh-based catalysts; − systems that provide the broadest substrate scope utilize tethered-aldehydes, including, PR 2 , alkene, NR 2 , , OH, − and SR groups, − in combination with Rh-chelated phosphine catalysts (Scheme B). The generally proposed mechanism for these reactions involves oxidative addition of the aldehyde to give an acyl-hydride, followed by co-ordination and migratory insertion of the alkyne/alkene, and finally reductive elimination to form the enone/ketone (Scheme C). , A competitive process to productive hydroacylation occurs by bifurcation of the reaction pathway at the acyl-hydride intermediate.…”

Section: Introductionmentioning

confidence: 99%

Rh(DPEPhos)-Catalyzed Alkyne Hydroacylation Using β-Carbonyl-Substituted Aldehydes: Mechanistic Insight Leads to Low Catalyst Loadings that Enables Selective Catalysis on Gram-Scale

et al. 2018

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The detailed mechanism of the hydroacylation of β-amido-aldehyde, 2,2-dimethyl-3-morpholino-3-oxopropanal, with 1-octyne using [Rh( cis-κ--DPEPhos)(acetone)][BAr]-based catalysts, is described [Ar = (CF)CH]. A rich mechanistic landscape of competing and interconnected hydroacylation and cyclotrimerization processes is revealed. An acyl-hydride complex, arising from oxidative addition of aldehyde, is the persistent resting state during hydroacylation, and quaternary substitution at the β-amido-aldehyde strongly disfavors decarbonylation. Initial rate, KIE, and labeling studies suggest that the migratory insertion is turnover-limiting as well as selectivity determining for linear/branched products. When the concentration of free aldehyde approaches zero at the later stages of catalysis alkyne cyclotrimerization becomes competitive, to form trisubstituted hexylarenes. At this point, the remaining acyl-hydride turns over in hydroacylation and the free alkyne is now effectively in excess, and the resting state moves to a metallacyclopentadiene and eventually to a dormant α-pyran-bound catalyst complex. Cyclotrimerization thus only becomes competitive when there is no aldehyde present in solution, and as aldehyde binds so strongly to form acyl-hydride when this happens will directly correlate to catalyst loading: with low loadings allowing for free aldehyde to be present for longer, and thus higher selectivites to be obtained. Reducing the catalyst loading from 20 mol % to 0.5 mol % thus leads to a selectivity increase from 96% to ∼100%. An optimized hydroacylation reaction is described that delivers gram scale of product, at essentially quantitative levels, using no excess of either reagent, at very low catalyst loadings, using minimal solvent, with virtually no workup.

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ChemInform Abstract: Hydroacylation of 1‐Alkene with 2‐(Diphenylphosphino)benzaldehyde by Rh(I).

Cited by 6 publications

References 0 publications

Rhodium-Catalyzed Regioselective Formal Hydroacylation of Vinyl Epoxides toward Esters Involving β-Carbon Cleavage

Rhodium-Catalyzed Regioselective Formal Hydroacylation of Vinyl Epoxides toward Esters Involving β-Carbon Cleavage

Teaching Aldehydes New Tricks Using Rhodium- and Cobalt-Hydride Catalysis

Rh(DPEPhos)-Catalyzed Alkyne Hydroacylation Using β-Carbonyl-Substituted Aldehydes: Mechanistic Insight Leads to Low Catalyst Loadings that Enables Selective Catalysis on Gram-Scale

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