The source of oxygen in cerium-catalyzed α-hydroxylation of β-dicarbonyl compounds

Rössle, Michael; Christoffers, Jens

doi:10.1016/j.tet.2009.09.024

Cited by 20 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The precatalyst in our case is aC e III salt. [26] In the catalytic cycle, dissociationo fc omplex 17 b liberates the ligand 18 and Ce III is finally reoxidized to Ce IV by air (upper cyclei nS cheme 7). [25] The anionic ligand then facilitates the oxidationo fC e III to Ce IV with dioxygen and the Ce IVdiketonato complex 17 a is formed.…”

Section: Discussionmentioning

confidence: 85%

“…Formation of ar adical species 17 b with spin density at the a-position can be proposed as ligand-to-metal charge transfer within Ce IV -diketonato complex 17 a. [26] In the catalytic cycle, dissociationo fc omplex 17 b liberates the ligand 18 and Ce III is finally reoxidized to Ce IV by air (upper cyclei nS cheme 7). Obviously,c oordination of Ce III to b-oxoesters shifts the redox potential and makes this air oxidation possible.…”

Section: Discussionmentioning

confidence: 99%

“…The anionic ligand then facilitates the oxidation of Ce III to Ce IV with dioxygen and the Ce IV –diketonato complex 17 a is formed. Formation of a radical species 17 b with spin density at the α‐position can be proposed as ligand‐to‐metal charge transfer within Ce IV –diketonato complex 17 a . In the catalytic cycle, dissociation of complex 17 b liberates the ligand 18 and Ce III is finally reoxidized to Ce IV by air (upper cycle in Scheme ).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Formation of δ‐Lactones with anti‐Baeyer–Villiger Regiochemistry: Investigations into the Mechanism of the Cerium‐Catalyzed Aerobic Coupling of β‐Oxoesters with Enol Acetates

Geibel

Dierks

Müller

et al. 2017

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

The cerium-catalyzed, aerobic coupling of β-oxoesters with enol acetates and dioxygen yields δ-lactones with a 1,4-diketone moiety. In contrast to the Baeyer-Villiger oxidation (BVO), where the higher substituted residue migrates; in the case of this oxidative C-C coupling reaction, the less substituted alkyl residue undergoes a 1,2-shift. An endoperoxidic oxycarbenium ion comparable to the Criegee intermediate in the BVO is proposed as a reaction intermediate and submitted to conformational analysis by computational methods. As a result, the inverse regiochemistry is explained by a primary stereoelectronic effect. A Hammett analysis using different donor- and acceptor-substituted enol esters provides support for the oxycarbenium ion being the crucial intermediate in the rate determining step of the conversion. An overall mechanism is suggested with a radical chain reaction for the formation of endoperoxides from β-oxoesters, enol acetates and dioxygen with a cerium(IV) species as initiating reagent.

show abstract

Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Formation of δ‐Lactones with anti‐Baeyer–Villiger Regiochemistry: Investigations into the Mechanism of the Cerium‐Catalyzed Aerobic Coupling of β‐Oxoesters with Enol Acetates

Geibel

Dierks

Müller

et al. 2017

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…CeCl 3 is a very useful metal catalyst, whose unique behavior is used to synthesis various heterocycle. 1a, [17][18][19][20][21] Table 1). 22,23 Various functional groups on the aldehyde (2) with OPD (1) is also examine.…”

Section: Introductionmentioning

confidence: 99%

Metal Catalyzed Synthesis of Pentose-Sugar-Based Chiral 2-Substituted-1H-Benzimidazoles

Halder¹

2020

Preprint

View full text Add to dashboard Cite

A metal catalyzed synthetic protocol has been developed using Ti(OBu)4-CeCl3 combo catalyst for chemoselective cyclocondensation cumoxidation under mild reaction conditions toward synthesis of a new class of optically pure compounds, 2-(6-benzyloxy-2,2-dimethyl-tetrahydro-furo[2,3-d][1,3]dioxol-5-yl)-6a,10a-dihydro-1H-anthra[1,2-d] imidazole-6,11-dione. All pentose-sugar-based aldehydes react with varies substituted dimethyl, 4-benzoyl and benzoquinoyl o-aromatic diamines (OAD) to afford desired chiral benzimidazoles with excellent isolated yield (77%-88%). In this suitable method chiral 2-Substituted-1H-Benzimidazoles were syntheses in high yields without using any hazardous chemicals or harmful acids. Normal aromatic aldehyde also reacts with varies o-aromatic diamines (OAD) give rise to known 2-Aryl-1H-benzimidazoles. All the target chiral 2-Substituted-1H-Benzimidazoles were characterized by FT-IR, NMR spectral and HR-MS data and also verified M.P of normal aromatic 2-Substituted-1H-benzimidazoles from literature.

show abstract

“…7 Suzuki and coworkers reported a two-step method involving the hydroxylation of isoxalium salts by using sodium hypochlorite as an oxidant. 8 Recently, oxidation by molecular oxygen catalyzed by transition-metal catalysts (manganese, 9 cerium, 10 or palladium 11 ) or by diiodine 12 has been used to synthesize 2-hydroxy-1,3-dicarbonyl compounds. From an economic and ecological point of view, the oxidation of dicarbonyl compounds by air is optimal.…”

mentioning

confidence: 99%

2-Hydroxylation of 1,3-Diketones with Atmospheric Oxygen

et al. 2015

Synlett

View full text Add to dashboard Cite

show abstract

The source of oxygen in cerium-catalyzed α-hydroxylation of β-dicarbonyl compounds

Cited by 20 publications

References 22 publications

Formation of δ‐Lactones with anti‐Baeyer–Villiger Regiochemistry: Investigations into the Mechanism of the Cerium‐Catalyzed Aerobic Coupling of β‐Oxoesters with Enol Acetates

Formation of δ‐Lactones with anti‐Baeyer–Villiger Regiochemistry: Investigations into the Mechanism of the Cerium‐Catalyzed Aerobic Coupling of β‐Oxoesters with Enol Acetates

Metal Catalyzed Synthesis of Pentose-Sugar-Based Chiral 2-Substituted-1H-Benzimidazoles

2-Hydroxylation of 1,3-Diketones with Atmospheric Oxygen

Contact Info

Product

Resources

About