The reaction of enols with superoxide anion radical [02???]1. Synthesis of 2,3-unsaturated-δ-valerolactones.
作者:Aryeh A. Frimer、Pessia Gilinsky-Sharon、Gladis Aljadeff
DOI:10.1016/s0040-4039(00)87089-6
日期:1982.1
4-Hydroxycoumarin ( and ) as well as 2-hydroxy-2,5-cyclohexadien-1-ones – were reacted with KO2/18-crown-6 in benzene. Initial deprotonation of the enol hydrogen was followed by nucleophilic attack by O2/t- (for and ) and/or autoxidation of the resulting anion (for and –). A convenient synthesis of 2,3-unsaturated-δ-valerolactones from the corresponding 2-cyclohexen-1-ones is also described.
Oxacycloalkenones are prepared by reacting a cycloalkenone with a base in the presence of a dioxygen source in a suitable solvent and isolating the desired product. 1-Hydroxy 2-oxa-3-oxo-.DELTA..sup.4 steroids are convenient synthetic precursors to 2-oxa-3-oxo-.DELTA..sup.4 steroids which find use in modern clinical therapy.