Synthesis of γ-halogenated ketones via the Ce(IV)-mediated oxidative coupling of cyclobutanols and inorganic halides

Casey, Brian M.; Eakin, Cynthia A.; Flowers, Robert A.

doi:10.1016/j.tetlet.2008.12.114

Cited by 44 publications

(13 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cerium(IV) ammonium nitrate (CAN) is a versatile, inexpensive and nontoxic single-electron oxidizing reagent commonly used in organic synthesis [12–14]. In a previous study, we showed that when 6-phenyl-2,4-hexanedione ( 1a ) is oxidized by CAN in MeCN in the absence of a radicophile, 3-phenylpropionic acid ( 2a* ) is obtained exclusively over the cyclized 2-tetralone product 2a (Scheme 1) [15].…”

Section: Introductionmentioning

confidence: 99%

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

Casey¹,

Sadasivam²,

Flowers³

2013

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

SummaryThe synthesis of 2-tetralones through the cyclization of δ-aryl-β-dicarbonyl substrates by using CAN is described. Appropriately functionalized aromatic substrates undergo intramolecular cyclizations generating 2-tetralone derivatives in moderate to good yields. DFT computational studies indicate that successful formation of 2-tetralones from δ-aryl-β-dicarbonyl radicals is dependent on the stability of the subsequent cyclohexadienyl radical intermediates. Furthermore, DFT computational studies were used to rationalize the observed site selectivity in the 2-tetralone products.

show abstract

Section: Introductionmentioning

confidence: 99%

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

Casey¹,

Sadasivam²,

Flowers³

2013

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Aerobic Benzylic C-H Oxidation, Etherification, and Acetamidation Full spectroscopic data were described for new compounds. Compound 37b, 41) f, 42) g, 43) h, 44) i, 45) j, 46) l, 47) m, 48) and n 49) are known compounds.…”

Section: General Procedures For Hydrogenolysis Of Benzyl Ether (Procedmentioning

confidence: 99%

Enhanced Structural Variety of Nonplanar <i>N</i>-Oxyl Radical Catalysts and Their Application to the Aerobic Oxidation of Benzylic C–H Bonds

Kadoh

Oisaki

Kanai

2016

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

The design and synthesis of structurally variable, nonplanar N-oxyl radical catalysts and their application to the aerobic oxidation, etherification, and acetoamidation of benzylic C-H bonds are described. The catalytic oxidation of C-H bonds represents a powerful tool to synthesize oxygenated functional molecules from simple hydrocarbons in a straightforward way. Electron-deficient N-oxyl radical catalysts, such as phthalimidoyl N-oxyl (PINO) radical, generated from N-hydroxyphthalimide (1), have attracted much attention because of their applications in the oxidation of C-H bonds with high bond dissociation energy (BDE). However, a few sites in 1 are available for structural modifications and improvements of the catalytic performance. By replacing one carbonyl group in 1 with a trifluoromethyl (CF 3 )-substituted sp 3 -carbon, we generated an additional tunable site and a nonplanar backbone, while retaining the desirable electronwithdrawing properties and increasing the lipophilicity with respect to 1. We synthesized a variety of Nhydroxy pre catalysts containing such a CF 3 moiety, and investigated their utility in the aerobic oxidation of benzylic C-H bonds. Precatalysts with electron-withdrawing substituents, such as trifluoroethoxy and the acetophenone moieties, afforded higher yields than a corresponding methoxy-substituted analogue. The introduction of substituents at the aromatic ring was also effective, as evident from the performance of 7-CF 3 and 4,5,6,7-tetrafluoro precatalysts. Especially the combination of trifluoroethoxy-and 4,5,6,7-tetrafluoro substitution afforded a superior performance. These catalyst systems exhibited high functional group tolerance during the aerobic oxidation of C-H bonds, and benzylic etherification and Ritter-type reactions could be carried out at room temperature when a selected precatalyst and N-bromosuccinimide (NBS) were used.

show abstract

“…173 Recently, Flowers et al have shown that the selective oxidation of an inorganic anion in the presence of 1-substituted cyclopropanol and 1-substituted cyclobutanol led to the formation of b-and g-substituted ketones, respectively (Scheme 33). 174,175 The formation of b-substituted ketones was achieved using anions like SCN(À), N 3 (À) and halide while g-substituted ketones were obtained using halide ion. 175 The inorganic radical generated from the anion added to cyclopropanol leading to a radical intermediate, which on subsequent oxidation followed by deprotonation afforded the final product.…”

Section: Miscellaneous Transformationsmentioning

confidence: 99%

“…174,175 The formation of b-substituted ketones was achieved using anions like SCN(À), N 3 (À) and halide while g-substituted ketones were obtained using halide ion. 175 The inorganic radical generated from the anion added to cyclopropanol leading to a radical intermediate, which on subsequent oxidation followed by deprotonation afforded the final product.…”

Section: Miscellaneous Transformationsmentioning

confidence: 99%

Recent advances in CAN mediated reactions in organic synthesis

Nair

Deepthi

2009

Tetrahedron

View full text Add to dashboard Cite

Synthesis of γ-halogenated ketones via the Ce(IV)-mediated oxidative coupling of cyclobutanols and inorganic halides

Cited by 44 publications

References 21 publications

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

Mechanistic studies on the CAN-mediated intramolecular cyclization of δ-aryl-β-dicarbonyl compounds

Enhanced Structural Variety of Nonplanar <i>N</i>-Oxyl Radical Catalysts and Their Application to the Aerobic Oxidation of Benzylic C–H Bonds

Recent advances in CAN mediated reactions in organic synthesis

Contact Info

Product

Resources

About