Unexpected formation of a 1,2-diketone from a 1,3-diketone mediated by lanthanides

Oxone-Mediated Oxidative Cleavage of β-Keto Esters and 1,3-Diketones to α-Keto Esters and 1,2-Diketones in Aqueous Medium

“…Methyl acetate (3 mmol, 222 mg) and benzaldehyde (6 mmol, 636 μL) were used according to the general procedure. The reaction was completed in 2 h (450 mg, 83%); 1 General Jones Oxidation for the Synthesis of Methyl 3-Oxo-3-phenylpropionate (7), tert-Butyl 3-Oxopent-4-enoate ( 8), and 6-Phenylhexane-2,4-dione (15). 44 A 1 mmol portion of the corresponding hydroxy ester or hydroxy ketone (methyl 3-hydroxy-3phenylpropanoate, tert-butyl 3-hydroxy-pent-4-enoate, and 5-hydroxy-1-phenylhexan-3-one, respectively) was dissolved in 5 mL of acetone.…”

“…The reaction was completed in 1 h. The product appeared as a mixture of keto−enol forms in a 1/1 ratio. (165 mg, 97%); keto form: 1 H NMR (300 MHz; CDCl 3 ; Me 4 Si) δ 1.44 (s, 9H), 3.51 (s, 2H), 5.90 (d, J = 11.2 Hz, 1H), 6.23 (d, J = 17.6 Hz, 1H), 6.37 (dd, J = 17.6, 11.2 Hz, 1H); 13 6-Phenylhexane-2,4-dione (15). 5-Hydroxy-1-phenylhexan-3one (1 mmol, 192 mg) and Jones reagent (360 μL) were used.…”

“…1,2-Diketones have also shown interesting applications as photosensitive agents and photoinitiators. , The practical and efficient synthesis of α-keto esters and 1,2-diketones remains an interesting and challenging goal. Most of the reported synthetic methodologies utilize hazardous and toxic reagents or catalysts, − while others require complicated time-consuming procedures − under harsh and unusual conditions. − Furthermore, in some cases, in an effort to minimize the reaction time, expensive reagents have been utilized. , An efficient method for the preparation of α-keto esters and 1,2-diketones has been published previously by Yang and co-workers . They successfully demonstrated the synthesis of α-keto esters by the dimethyldioxirane mediated oxidative cleavage of cyanoketophosphoranes.…”

Applications of Oxone® in Organic Synthesis: An Emerging Green Reagent of Modern Era

“…1,2‐Diketones also have fascinating applications as photosensitive agents and photoinitiators. Unfortunately, most of the reported synthetic methodologies utilize either hazardous/toxic/expensive reagents and/or catalysts or time‐consuming procedures underneath harsh reaction conditions [306,307] . Therefore, the practical synthesis of α ‐ketoesters and 1,2‐diketones remains an ongoing challenge to the synthetic chemists.…”

“…Unfortunately, most of the reported synthetic methodologies utilize either hazardous/toxic/expensive reagents and/or catalysts or time-consuming procedures underneath harsh reaction conditions. [306,307] Therefore, the practical synthesis of α-ketoesters and 1,2-diketones remains an ongoing challenge to the synthetic chemists. In this regard, Stergiou et aldeveloped a versatile eco-friendly one-step method for the synthesis of α-ketoesters 386 a-f and 1,2-diketones 386 g-j in moderate to excellent yields via an oxidative cleavage of carbonyl compoundsusing nontoxic and low-cost reagents like oxone and AlCl 3 in an aqueous medium at room temperature (Scheme 124).…”