A number of model compounds corresponding to substructures of the fungicidal macrolide soraphen A were prepared from the lactone 3. This lactone was obtained degradatively from soraphen A using the mild Japp-Klingemann variant of the retro-aldol reaction and ozonolysis of the double bond. Addition of ester enolates,ta the lactone 3 led to the isolation of unstable hemiacetals which were converted to their anomerically stabilized tautomers on chromatography or prolonged standing in solution. Because of the unusual stability of the initially formed hemiacetals it was possible to define the structures of the transition states of the addition of enolates to a lactone in unprecedented detail.
A number of model compounds corresponding to substructures of the fungicidal macrolide soraphen A were prepared from the lactone 3. This lactone was obtained degradatively from soraphen A using the mild Japp-Klingemann variant of the retro-aldol reaction and ozonolysis of the double bond. Addition of ester enolates,ta the lactone 3 led to the isolation of unstable hemiacetals which were converted to their anomerically stabilized tautomers on chromatography or prolonged standing in solution. Because of the unusual stability of the initially formed hemiacetals it was possible to define the structures of the transition states of the addition of enolates to a lactone in unprecedented detail.
作者:Bernard Loubinoux、Jean-Luc Sinnes、Anthony C. O'Sullivan、Tammo Winkler
DOI:10.1021/jo00109a028
日期:1995.2
A number of model compounds corresponding to substructures of the fungicidal macrolide soraphen A were prepared from the lactone 3. This lactone was obtained degradatively from soraphen A using the mild Japp-Klingemann variant of the retro-aldol reaction and ozonolysis of the double bond. Addition of ester enolates,ta the lactone 3 led to the isolation of unstable hemiacetals which were converted to their anomerically stabilized tautomers on chromatography or prolonged standing in solution. Because of the unusual stability of the initially formed hemiacetals it was possible to define the structures of the transition states of the addition of enolates to a lactone in unprecedented detail.