Manganese‐Catalyzed Hydrogen‐Autotransfer C−C Bond Formation: α‐Alkylation of Ketones with Primary Alcohols

Peña‐López, Miguel; Piehl, Patrick; Elangovan, Saravanakumar; Neumann, Helfried; Beller, Matthias

doi:10.1002/ange.201607072

Cited by 86 publications

(18 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given the importance of ligand-assisted mechanisms in hydrogen transfer catalysis, our working hypothesis is that involvement of the acidic hydrogens in the methylene backbone of dppm may be important; recent reports in related chemistry support this hypothesis. 25 , 36 , 37 …”

Section: Catalyst Testingmentioning

confidence: 99%

Manganese Diphosphine and Phosphinoamine Complexes Are Effective Catalysts for the Production of Biofuel Alcohols via the Guerbet Reaction

et al. 2020

View full text Add to dashboard Cite

We report a variety of manganese-based catalysts containing both chelating diphosphine (bis(diphenylphosphino)methane (dppm: 1 , 2 , and 7 ) or 1,2-bis(diphenylphosphino)ethane (dppe: 3 )), and mixed-donor phosphinoamine (2-(diphenylphosphino)ethylamine (dppea: 4 – 6 )) ligands for the upgrading of ethanol and methanol to the advanced biofuel isobutanol. These catalysts show moderate selectivity up to 74% along with turnover numbers greater than 100 over 90 h, with catalyst 2 supported by dppm demonstrating superior performance. The positive effect of substituting the ligand backbone was also displayed with a catalyst supported by C-phenyl-substituted dppm ( 8 ) having markedly improved performance compared to the parent dppm catalysts. Catalysts supported by the phosphinoamine ligand dppea are also active for the upgrading of ethanol to n -butanol. These results show that so-called PNP-pincer ligands are not a prerequisite for the use of manganese catalysts in Guerbet chemistry and that simple chelates can be used effectively.

show abstract

Section: Catalyst Testingmentioning

confidence: 99%

Manganese Diphosphine and Phosphinoamine Complexes Are Effective Catalysts for the Production of Biofuel Alcohols via the Guerbet Reaction

et al. 2020

View full text Add to dashboard Cite

show abstract

“…[16] In 2016, Milstein and co-workers reported the first manganese-catalyzed ADC of alcohols with amines. [28] Based on the borrowing hydrogen approach, Calkylations of ketones [29] and Nalkylations of amines [30] have also been developed. [28] Based on the borrowing hydrogen approach, Calkylations of ketones [29] and Nalkylations of amines [30] have also been developed.…”

mentioning

confidence: 99%

Manganese‐Catalyzed Direct Olefination of Methyl‐Substituted Heteroarenes with Primary Alcohols

2018

View full text Add to dashboard Cite

Herein, we present the first catalytic direct olefination of methyl-substituted heteroarenes with primary alcohols through an acceptorless dehydrogenative coupling. The reaction is catalyzed by a complex of the earth-abundant transition metal manganese that is stabilized by a bench-stable NNN pincer ligand derived from 2-hydrazinylpyridine. The reaction is environmentally benign, producing only hydrogen and water as byproducts. A large number of E-disubstituted olefins were selectively obtained with high efficiency.

show abstract

“…[6] Owing to economic constraint and sustainability concerns,t he replacement of platinum metals by first-row-based metals could be an attractive alternative. Recent reports described the use of iron, [7] cobalt [8] and manganese [9] as non preciousm etals in hydrogen autotransfer processes. However,a ll these complexes requiredat emperature threshold of 140 8Ca nd/ore xpensive phosphine ligands.…”

mentioning

confidence: 99%

Alkylation of Ketones Catalyzed by Bifunctional Iron Complexes: From Mechanistic Understanding to Application

et al. 2017

View full text Add to dashboard Cite

Alkylation of ketones usually involves halides or pseudohalides such as tosylate and triflate derivatives in the presence of a stoichiometric amount of as trong base. [1] Such methodology generates wastes, as all these electrophiles are prepared from alcohols, and requires the use of hazardous chemical materials. Synthetic chemists seek nowadays for more environmentally friendly ways to construct carbon-carbon bonds. In recent years, several efficient strategies were proposed for their creation:i )directly from two simple carbon-hydrogen bonds (catalytic dehydrogenative cross-coupling reaction), [2] andi i) from ketonesa nd alcohols (hydrogen autotransfero rb orrowing hydrogen strategy). [3] Carbon-carbon bond formation via the borrowing hydrogen strategy is ap owerful strategy for the alkylation of ketones (Scheme1). [3] Advantages of this approach are the use of easily-to-handle alcohols, asasourceo fa lkylating reagents, andt he formationo fw ater as the sole byproduct. Indeed, following as implified mechanism,t he alcohol is initially oxidized (dehydrogenation step), and then an aldolizationdehydration step liberates an enone intermediate, whichc an be reduced into ak etone (Scheme 1).Many efficient catalysts are based on expensive noble metals such as iridium, [4] ruthenium [5] or rhodium. [6] Owing to economic constraint and sustainability concerns,t he replacement of platinum metals by first-row-based metals could be an attractive alternative. Recent reports described the use of iron, [7] cobalt [8] and manganese [9] as non preciousm etals in hydrogen autotransfer processes. However,a ll these complexes requiredat emperature threshold of 140 8Ca nd/ore xpensive phosphine ligands. The scope of substrates could also be rather limited. As example, Darcel and co-workers showed recently that only aromatic ketones could be engaged in alkylation reactions in the presence of an in situ iron catalystg enerated from Knçlker's complex and triphenylphosphine. [10] Moreover,y ields were moderate andn om echanism was proposed. [11] Then, even if these works pavet he way to new opportunities in sustainable chemistry,s omel imitationsw ere still present,amechanistic understanding of this iron-catalyzed alkylation reaction and someimprovementwere needed.In our ongoing work on iron-catalyzed reduction, [12] we have recently brought to light that cyclopentadienone iron tricar-Cyclopentadienone iron dicarbonyl complexes were applied in the alkylation of ketones with variousa liphatic and aromatic ketones and alcohols via the borrowing hydrogen strategy in mild reactionc onditions. DFT calculations and experimental works highlight the role of the transition metal Lewis pairs and the base. These iron complexes demonstrated ab road applicability in mild conditions and extended the scope of substrates.Scheme1.Simplified acceptedm echanism of alkylation of ketones.

show abstract

Manganese‐Catalyzed Hydrogen‐Autotransfer C−C Bond Formation: α‐Alkylation of Ketones with Primary Alcohols

Abstract: Scheme 3. Manganese-catalyzed a-alkylationo fa)2-oxindole and b) estrone 3-methyl ether and testosteronew ith alcohols. Yields are for the isolated product.Scheme 4. Plausible mechanism for the manganese-catalyzed a-alkylation of ketones with alcohols.

Cited by 86 publications

References 74 publications

Manganese Diphosphine and Phosphinoamine Complexes Are Effective Catalysts for the Production of Biofuel Alcohols via the Guerbet Reaction

Manganese Diphosphine and Phosphinoamine Complexes Are Effective Catalysts for the Production of Biofuel Alcohols via the Guerbet Reaction

Manganese‐Catalyzed Direct Olefination of Methyl‐Substituted Heteroarenes with Primary Alcohols

Alkylation of Ketones Catalyzed by Bifunctional Iron Complexes: From Mechanistic Understanding to Application

Contact Info

Product

Resources

About