A Series of Cinchona-Derived <i>N</i>-Oxide Phase-Transfer Catalysts: Application to the Photo-Organocatalytic Enantioselective α-Hydroxylation of β-Dicarbonyl Compounds

Wang, Yakun; Yin, Hang; Tang, Xiaofei; Wu, Yufeng; Meng, Qingwei; Gao, Zheng-Ming

doi:10.1021/acs.joc.6b00856

Cited by 59 publications

(15 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If tetraphenylporphyrin (TPP) acted as a photosensitizer, the reaction gave products 115 in excellent yields and high enantiomeric purities. The catalysts were easily separated and reused without any significant loss of activity or enantioselectivity (Scheme ) …”

Section: Enantioselective Organocatalysis With Lightmentioning

confidence: 99%

Green Asymmetric Organocatalysis

et al. 2020

View full text Add to dashboard Cite

Scheme12. At extile-supported organocatalyst for anhydride opening; MTBE = methyl tert-butyl ether.Scheme13. Organocatalytic aldolreaction conductedb yu sing the continuous-flow technique.Scheme11. PS-immobilized catalyst C32 for the amination of oxindoles 32.Scheme40. Photo-organocatalytic hydroxylation of ketoesters and amides. LED = light-emitting diode.Scheme41. Light-promoted cyclization.Scheme42. Light-promoted alkylation of aldehydes. EWG = electron-withdrawinggroup.Scheme49. Primary-aminec atalyzed light-promoted alkylations of dicarbonyl compounds.Scheme48. Light-promoted organocatalytic Michael additions.

show abstract

Section: Enantioselective Organocatalysis With Lightmentioning

confidence: 99%

Green Asymmetric Organocatalysis

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Besides making use of oxygen or air together with a stoichiometric activator/reductant as described above ( Scheme 7 and Scheme 8 ), the photooxygenation of prochiral substrates like β-ketoesters 1 with O 2 or air in the presence of a chiral PTC and TPP (tetraphenylporphyrin) as a photosensitizer has recently been reported to proceed with satisfying selectivities by the groups of Meng and Gao [ 114 – 115 ]. In their first report [ 114 ], they made use of the classical cinchona catalyst A5 together with catalytic amounts of TPP under irradiation with a 100 W halogen lamp with air as the oxygen source.…”

Section: Reviewmentioning

confidence: 99%

“…In their first report [ 114 ], they made use of the classical cinchona catalyst A5 together with catalytic amounts of TPP under irradiation with a 100 W halogen lamp with air as the oxygen source. Very recently, they then introduced the N -oxide-containing PTC A6 , which gave even higher selectivities and was successfully used under yellow LED (3 W) irradiation [ 115 ] ( Scheme 9 ).…”

Section: Reviewmentioning

confidence: 99%

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

Schörgenhumer¹,

Tiffner²,

Waser³

2017

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

Chiral phase-transfer catalysis is one of the major catalytic principles in asymmetric catalysis. A broad variety of different catalysts and their use for challenging applications have been reported over the last decades. Besides asymmetric C–C bond forming reactions the use of chiral phase-transfer catalysts for enantioselective α-heterofunctionalization reactions of prochiral nucleophiles became one of the most important field of application of this catalytic principle. Based on several highly spectacular recent reports, we thus wish to discuss some of the most important achievements in this field within the context of this review.

show abstract

“…N-oxides of heterocycles are of great importance due to their widespread applicability, including, but not limited to, manufacturing chirality chemosensors [1], oxidizing agents in annulation reactions [2], intramolecular oxidants in Baeyer-Villiger reaction of ketones [3], directing group and source of oxygen atom in sulfonylation reactions [4], phase-transfer catalysts in enantioselective transformations [5], starting materials in C-C bond forming processes [6][7][8][9], or in the synthesis of 2-aminopyridines [10] and N-azine sulfoximines [11]. Recently published papers have discussed the cycloaddition reactions of N-oxides [12], their photochemistry [13,14] and their applications in organocatalysis [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of 1,10-Phenanthroline-mono-N-oxides

et al. 2021

View full text Add to dashboard Cite

N-oxides of N-heteroaromatic compounds find widespread applications in various fields of chemistry. Although the strictly planar aromatic structure of 1,10-phenanthroline (phen) is expected to induce unique features of the corresponding N-oxides, so far the potential of these compounds has not been explored. In fact, appropriate procedure has not been reported for synthesizing these derivatives of phen. Now, we provide a straightforward method for the synthesis of a series of mono-N-oxides of 1,10-phenanthrolines. The parent compounds were oxidized by a green oxidant, peroxomonosulfate ion in acidic aqueous solution. The products were obtained in high quality and at good to excellent yields. A systematic study reveals a clear-cut correlation between the basicity of the compounds and the electronic effects of the substituents on the aromatic ring. The UV spectra of these compounds were predicted by DFT calculations at the TD-DFT/TPSSh/ def2-TZVP level of theory.

show abstract

A Series of Cinchona-Derived N-Oxide Phase-Transfer Catalysts: Application to the Photo-Organocatalytic Enantioselective α-Hydroxylation of β-Dicarbonyl Compounds

Cited by 59 publications

References 49 publications

Green Asymmetric Organocatalysis

Green Asymmetric Organocatalysis

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

Synthesis and Characterization of 1,10-Phenanthroline-mono-N-oxides

Contact Info

Product

Resources

About