- Temporary thio-derivatization in the synthesis of (+)-4-acetylbromoxone
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A stereocontrolled synthesis of the marine natural products (+)-bromoxone (1) and (+)-4-acetylbromoxone (2) is reported. The sequence features the enzymatic kinetic resolution of 4-hydroxycyclohexenone (6) via its S-benzyl adduct. Thereafter, a base-mediated elimination-silylation generated an optically active (-)-4S-4-tert-butyldimethylsilyoxycyclohexenone (5), which then underwent diastereoselective epoxidation. Saegusa-Ito oxidation enabled formation of the corresponding α,β-unsaturated ketone 13. Bromination-elimination and subsequent removal of the silicon protecting group afforded (+)-bromoxone (1) which was converted into (+)-(4S,5R,6R)-4-acetoxy-2- bromo-5,6-epoxycyclohex-2-enone (2) [(+)-4-acetylbromoxone]. Using a luciferase gene reporter assay ED50 for NFκB inhibition of 9 μM was determined.
- O'Byrne, Aisling,O'Reilly, Steven,Tighe, Catherine,Evans, Paul,Ciuffini, Laura,Gabriella Santoro
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p. 5936 - 5938
(2013/01/13)
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- Novel preparation of (-)-4-hydroxycyclohex-2-enone: Reaction of 4-hydroxycyclohex-2-enone and 4-hydroxycyclopent-2-enone with some thiols
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A new route to (R)-4-hydroxycyclohex-2-enone from cyclohexanedione monoketal (27% yield) commences with reaction of the ketal with nitrosobenzene catalysed by l-proline. 4-Hydroxycyclohex-2-enone and 4-hydroxycyclopent-2-enone react with thiols to afford
- Bickley, Jamie F.,Evans, Paul,Meek, Alastair,Morgan, Ben S.,Roberts, Stanley M.
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p. 355 - 362
(2007/10/03)
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- Facile biocatalytic syntheses of optically active 4-hydroxycyclohex-2-enone and 4-benzylthiacyclopent-2-enone
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Novozyme 435 (Candida antarctica Lipase B) effects the kinetic resolution of both 3-benzylthia-4-hydroxycyclopentanone and its six-membered ring analogue, providing a novel route to both enantiomers of 4-benzylthiacyclopent-2-enone and the two enantiomers of 4-hydroxycyclohex-2- enone, all in a state of very high optical purity.
- Morgan, Ben S.,Hoenner, Dorothee,Evans, Paul,Roberts, Stanley M.
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p. 2807 - 2809
(2007/10/03)
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