5-positions into dihydrofurans was developed. Using dimethylsulfoxonium methylide as the methylene-transferreagent, the α-pyrones were converted into dihydrofurans as major products and 1-methylthiopyran-1-oxides as minor products. The selectivity of the dihydrofuran formation was improved by optimizing the reaction conditions.
Polyketoenols and chelates. Glaucyrones and their reactions with magnesium methoxide
作者:S. Richard Baker、Leslie Crombie
DOI:10.1039/p19810000178
日期:——
complete ester exchange in the reaction of 3,3′-diacetyl-5,5′-bisethoxycarbonylglaucyrone (1) with excess of magnesiummethoxide, in accord with the mechanism proposed. On reaction with the latter reagent, the two new glaucyrones give aromatic penta-esters (11) and (14), and their mechanisms of formation are discussed. Heating these penta-esters effects cyclisation to xanthyrones having aromatic side-chain
Tautomerically symmetrical and unsymmetrical glaucyrones: reactions with magnesium methoxide as a chelating base
作者:S. Richard Baker、Leslie Crombie
DOI:10.1039/c39800000213
日期:——
The first tautomerically unsymmetrical glaucyrone has been made, along with a second symmetrical type; their reactions with magnesiummethoxide are informative of the part played by magnesiumchelates in the chemistry of multi-1,3-dicarbonyls.