- Substituent effects on the reaction mode between 2-hydroxybenzyl alcohol derivatives and MEM chloride: Synthesis and mechanistic aspects of seven- and ten-membered benzo-fused O,O-acetals
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The synthesis of (RS)-2- or (RS)-3-methoxy-2,3-dihydro-5H-1,4- benzodioxepins and (RS)-5- or (RS)-3-methoxy-2,3,5,6-tetrahydro-8H-benzo-[1,4,7] -trioxecins has been developed. The mechanism of such a reaction via the boron trifluoride etherate-promoted transformation of 2-(methoxyethoxymethoxy) benzyloxyacetaldehyde dimethyl acetals or 2-(methoxyethoxymethoxymethyl) phenyloxyacetaldehyde dimethyl acetals has been proposed. Transannular versions of the reaction results in the facile ring contraction of 12-membered intermediates to the 10- and to 7-membered benzene-fused O,O-acetals. The characterization of the by-products strongly supports the mechanisms proposed. Graphical Abstract.
- Saniger, Estrella,Díaz-Gavilán, Mónica,Delgado, Beatriz,Choquesillo, Duane,González-Pérez, Josefa M.,Aiello, Stefania,Gallo, Miguel á.,Espinosa, Antonio,Campos, Joaquín M.
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p. 11453 - 11464
(2007/10/03)
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