- Annulation of α-Formyl α,β-Unsaturated Ketones by a Michael Addition-Cyclization Sequence. A Versatile Synthesis of Alicyclic Six-Membered Rings.
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The potential generality of the annulation sequence shown in Scheme II (10 -> 11 -> 12 -> 13 -> 14/15) has been examined in model systems.Dehydrogenation of α-formylcyclohexanones 11a-d with 1 equiv of DDQ rapidly produces α,β-unsaturated α-formyl ketones
- Meyer, Walter L.,Brannon, Michael J.,Burgos, Celmira da G.,Goodwin, Thomas E.,Howard, Ralph W.
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p. 438 - 447
(2007/10/02)
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- 1,2-Disubstituted Ethanes As Possible Precursors For The Synthesis of Cannabis Spirans
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Three possible methods for converting suitable 1,2-disubstituted ethanes into Cannabis spirans have been investigated. 4',5-Dihydroxy-3-methoxybibenzyl underwent intramolecular o-p- and p-p-coupling with ferricyanide in a chloroform-aqueous potassium carbonate system, but yields were low: certain other oxidants did not succeed or gave only traces of product.A method for making 1-hydroxy-1-(3,5-dimethoxyphenylethyl)cyclohexan-4-one ethylene acetal or thioacetal via a Birch reaction is described: despite favourable precedent, acid-catalysed cyclisation led to octahydrophenanthrenones rather than spiro-ketones, whilst N,N-dimethylformamide dineopentyl acetal gave two olefins.Jacquesy's super-asid method for making spirocyclohexenones from a methoxylated bibenzyl was not applicable to the 3,4',5-trimethoxy-case, which would have given cannabispirenone methyl ether, presumably because of protonation of both aromatic systems.
- Crombie, Leslie,Crombie, W. Mary L.,Jamieson, Sally V.,Tuchinda Patoomratana,Whitaker, Alison J.
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p. 1485 - 1492
(2007/10/02)
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