Stability of cycloadducts obtained by high-pressure Diels-Alder reaction between 3,4-dimethoxyfuran and 1,4-benzoquinones: kinetic studies of retro-Diels-Alder reaction
Cycloaddition of 3,4-Dimethoxyfuran with 1,4-Benzoquinones under High Pressure
作者:Janusz Jurczak、Tomasz Ko??gluk、Marek Tkacz、Conrad Hans Eugster
DOI:10.1002/hlca.19830660122
日期:1983.2.2
High-pressure cycloaddition of 3,4-dimethoxyfuran with 1,4-benzoquinone, toluquinone and 2,3-dimethoxy-1,4-benzoquinone show, at 7 kbar and room temperature, prevailing formation of endo-isomers. Raising pressure (or temperature) results in a surprising increase of the exo-isomer. By catalytic hydrogenation of a mixture 3a/4a, followed by chromatography, the pure diastereomers 5 and 6 were obtained