Allylic and benzylic oxidation using cobalt(II) alkyl phosphonate modified silica

Tetrahedron Letters

Volumn 44, Issue 22, 2003, Pages 4283-4286

  Jurado Gonzalez, Magdalena ^a   Sullivan, Alice C ^a   Wilson, John R H ^a  

^a QUEEN MARY UNIVERSITY OF LONDON   (United Kingdom)

Author keywords

Benzylic; Cobalt; Immobilised reagents; Oxidation; Phosphonate; Silica; Steroids

Indexed keywords

ALLYL COMPOUND; BENZYL DERIVATIVE; COBALT DERIVATIVE; PHOSPHONIC ACID DERIVATIVE; SILICON DIOXIDE; TERT BUTYL HYDROPEROXIDE;

ARTICLE; CATALYSIS; OXIDATION;

EID: 0037725041     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(03)00833-5     Document Type: Article

References (21)

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15. Idealised structure assuming 100% condensation.
16. 3-n] n=1-3.
17. Unpublished results.
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20. 2EPS3 (1.21 g) and the resultant mixture was stirred for 1 h. The blue purple solid was filtered and washed with distilled water (1.5 L) and then with ethanol and ether and finally dried under reduced pressure, 120°C and 0.01 torr for 12 h, to afford CoEPS (1.13 g).
21. Typical procedure: A mixture containing the substrate (1 mmol) dissolved in acetonitrile (6 ml), cobalt(II) alkyl phosphonate silica catalyst (60 mg) and tert-butyl hydroperoxide (6 mmol in decane) was heated and stirred under an atmosphere of nitrogen at the temperature and period of time indicated in Tables 1 and 2. On completion the catalyst was filtered and washed well with dichloromethane. The combined filtrate was washed well with an aqueous sodium sulphite solution (10%) and then with water, dried and concentrated under reduced pressure. Purification where necessary, to remove traces of starting material, was by recrystallisation or by column chromatography.