118090-87-2Relevant academic research and scientific papers
OXYGEN HETEROCYCLES BY SULPHUR YLIDE ANNULATION. X. 3-HYDROXY-3,4,5,6-TETRAHYDRO-2H-1-BENZOXOCINS FROM 2-(4-OXOALKYL)PHENOLS AND DIMETHYLSULPHOXONIUM METHYLIDE
Arnone, Alberto,Bernardi, Rosanna,Bravo, Pierfrancesco,Frigerio, Massimo,Ticozzi, Calimero
, p. 87 - 94 (2007/10/02)
The synthesis of several 3-hydroxy-3,4,5,6-tetrahydro-2H-1-benzoxocins, 7, by dimethylsulphoxonium methylide reaction on 2-(4-oxoalkyl)phenols, 5, obtained in turn from o-benzyloxybenzaldehydes, 1, is reported.The formation of intermediate open-chain oxiranes 6 arising by a transfer of methylene from the ylide to the carbonyl group of the substrate and the highly regiospecific endo intramolecular cyclization to 3-hydroxy-3,4,5,6-tetrahydro-2H-1-benzoxocins, 7, have been followed by 1H NMR spectroscopy.The synthesis of the isomeric 2-hydroxymethyl-2,3,4,5-tetrahydro-1-benzoxepins, 9, from the same 2-(4-oxoalkyl)phenols, through methylenation by triphenylphosphonium methylide and MCPBA oxidation is also reported.Dehydration of the title compounds afforded dihydrobenzoxocins 11 - 13 which, upon catalytic hydrogenation, gave 3,4,5,6-tetrahydro-1-benzoxocins 14.A detailed 1H NMR study allowed assignment of the configurations and the preferred conformations of some tetrahydrobenzoxocins and tetrahydrobenzoxepins trisubstituted on the heterocyclic ring.
