Highly Selective Hydrogenation of Aromatic Ketones and Phenols Enabled by Cyclic (Amino)(alkyl)carbene Rhodium Complexes

Yu, Wu; Rao, Bin; Cong, Xuefeng; Zeng, Xiaoming

doi:10.1021/jacs.5b05868

Cited by 141 publications

(111 citation statements)

References 63 publications

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“…Zeng et al. have reported the selective hydrogenation of the aromatic ring of ketones and phenols using cyclic(amino)alkyl carbene rhodium complexes under H 2 (5 bar) . Notably, ruthenium arene complexes based on N‐donor ligands, such as ethylenediamine‐derived ligands have been identified as transfer hydrogenation catalysts, and therefore, we anticipated that these complexes could be used to achieve arene ring hydrogenation under precisely tuned reaction conditions.…”

Section: Introductionmentioning

confidence: 97%

Catalytic Hydrogenation of Arenes in Water Over In Situ Generated Ruthenium Nanoparticles Immobilized on Carbon

et al. 2017

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We describe a tandem process to generate active Ru nanoparticles (≈7 nm) immobilised in situ on carbon from an organometallic precursor and formic acid to afford the hydrogenation of a wide range of arenes and heteroarenes in yields up to 72 % with high conversions and selectivities for the desired products. The hydrogenation of several substrates analogous to lignin‐derived fragments to the corresponding alicyclic products was also achieved. Our experimental investigations evidenced that the observed enhanced activity for arene hydrogenation was driven by the unique structural advantages of the organometallic precursor to activate formic acid, in which the presence of a nitrogen ligand is crucial to achieve a high catalytic activity. TEM analysis revealed the formation of Ru0 nanoparticles, and Hg0 poisoning experiments support the heterogeneous nature of the active catalyst.

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Section: Introductionmentioning

confidence: 97%

Catalytic Hydrogenation of Arenes in Water Over In Situ Generated Ruthenium Nanoparticles Immobilized on Carbon

et al. 2017

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“…Most notably, CAAC‐Au I species were shown to be extremely robust catalysts (even under harsh conditions) for the hydroamination (with NH 3 or NH 2 ‐NH 2 ) of alkynes and allenes, showing the exceptional stability of the CAAC‐Au I moiety in such catalysts . Also noteworthy, the use of a CAAC‐supported Rh I catalyst (instead of a NHC analogue) was found to be crucial for high selectivity and activity in the catalytic hydrogenation of aromatic ketones, illustrating the interest of CAAC‐based metal species in catalysis …”

Section: Introductionmentioning

confidence: 98%

Cyclic(Alkyl)(Amino)Carbene (CAAC)‐Supported Zn Alkyls: Synthesis, Structure and Reactivity in Hydrosilylation Catalysis

Bruyere

Specklin

Gourlaouen

et al. 2019

Chemistry A European J

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The reactivity of ZnII dialkyl species ZnMe2 with a cyclic(alkyl)(amino)carbene, 1‐[2,6‐bis(1‐methylethyl)phenyl]‐3,3,5,5‐tetramethyl‐2‐pyrrolidinylidene (CAAC, 1), was studied and extended to the preparation of robust CAAC‐supported ZnII Lewis acidic organocations. CAAC adduct of ZnMe2 (2), formed from a 1:1 mixture of 1 and ZnMe2, is unstable at room temperature and readily undergoes a CAAC carbene insertion into the Zn−Me bond to produce the ZnX2‐type species (CAAC‐Me)ZnMe (3), a reactivity further supported by DFT calculations. Despite its limited stability, adduct 2 was cleanly ionized to robust two‐coordinate (CAAC)ZnMe+ cation (5+) and derived into (CAAC)ZnC6F5+ (7+), both isolated as B(C6F5)4− salts, showing the ability of CAAC for the stabilization of reactive [ZnMe]+ and [ZnC6F5]+ moieties. Due to the lability of the CAAC−ZnMe2 bond, the formation of bis(CAAC) adduct (CAAC)2ZnMe+ cation (6+) was also observed and the corresponding salt [6][B(C6F5)4] was structurally characterized. As estimated from experimental and calculations data, cations 5+ and 7+ are highly Lewis acidic species and the stronger Lewis acid 7+ effectively mediates alkene, alkyne and CO2 hydrosilylation catalysis. All supporting data hints at Lewis acid type activation–functionalization processes. Despite a lower energy LUMO in 5+ and 7+, their observed reactivity is comparable to those of N‐heterocyclic carbene (NHC) analogues, in line with charge‐controlled reactions for carbene‐stabilized ZnII organocations.

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“…[8] Thec ontrol of stereoselectivity in the catalytic hydrogenation of substituted arenes is another major challenge,ascis and trans stereoisomers are usually formed. [10][11][12][13][14] This approach enables the hydrogenation of aryl and heteroaryl boronate esters with retention of the boronate ester functional group (Scheme 1b). [10][11][12][13][14] This approach enables the hydrogenation of aryl and heteroaryl boronate esters with retention of the boronate ester functional group (Scheme 1b).…”

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confidence: 99%

“…[16,17] CAACs have found use as ancillary ligands in rhodium-catalyzed arene hydrogenations of aromatic ketones,phenols,fluoroarenes,and silylarenes. [11][12][13] We commenced our studies with the synthesis of the ortho-dimethyl-substituted CAAC-Rh complex ( Me CAAC)Rh(COD)Cl. [18] Ther elated aldiminium salt was deprotonated with lithium diisopropylamide (LDA), and then treated with [Rh(COD)Cl] 2 to afford the air-a nd moisturestable ( Me CAAC)Rh(COD)Cl complex in moderate yield (Scheme 2).…”

mentioning

confidence: 99%

Hydrogenation of (Hetero)aryl Boronate Esters with a Cyclic (Alkyl)(amino)carbene–Rhodium Complex: Direct Access to cis‐Substituted Borylated Cycloalkanes and Saturated Heterocycles

Ling

Zhang

et al. 2019

Angewandte Chemie

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We herein report the hydrogenation of substituted aryl-and heteroaryl boronate esters for the selective synthesis of cis-substituted borylated cycloalkanes and saturated heterocycles.Acyclic (alkyl)(amino)carbene-ligated rhodium complex with two dimethyl groups at the ortho-alkyl scaffold of the carbene showed high reactivity in promoting the hydrogenation, therebye nabling the hydrogenation of (hetero)arenes with retention of the synthetically valuable boronate group. This process constitutes ac lean, atom-economic,a swell as chemo-and stereoselective route for the generation of cisconfigured, diversely substituted borylated cycloalkanes and saturated heterocycles that are usually elusive and difficult to prepare.

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Highly Selective Hydrogenation of Aromatic Ketones and Phenols Enabled by Cyclic (Amino)(alkyl)carbene Rhodium Complexes

Cited by 141 publications

References 63 publications

Catalytic Hydrogenation of Arenes in Water Over In Situ Generated Ruthenium Nanoparticles Immobilized on Carbon

Catalytic Hydrogenation of Arenes in Water Over In Situ Generated Ruthenium Nanoparticles Immobilized on Carbon

Cyclic(Alkyl)(Amino)Carbene (CAAC)‐Supported Zn Alkyls: Synthesis, Structure and Reactivity in Hydrosilylation Catalysis

Hydrogenation of (Hetero)aryl Boronate Esters with a Cyclic (Alkyl)(amino)carbene–Rhodium Complex: Direct Access to cis‐Substituted Borylated Cycloalkanes and Saturated Heterocycles

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