REVERSE KETAL-ACETAL REARRANGEMENT OF LEVOGLUCOSENONE AND CYCLOHEXANONE MICHAEL ADDUCTS AND THE POSSIBILITIES OF ITS USE IN THE SYNTHESIS OF NATIVE TOPOLOGY LACTONES
DOI:
https://doi.org/10.1007/4934Keywords:
аддукты Михаэля, лактоны, левоглюкозенон, кетализацияAbstract
Heating of solutions of the internal hemiketal, obtained by opening the 1,6-anhydro bridge in the Michael adduct of levoglucosenone and cyclohexanone, under reflux in THF or diglyme in the presence of NaH or Na, respectively, leads to the reduction of the hemiketal group to the ether group and oxidation of its alcohol component to the hemiacetal group. The conditions for the reverse transformation were established. Some transformations of the obtained cyclic hemiacetal have been studied. Direct methylation attempts with MeMgI in order to introduce a substituent into the 1,6-anhydro bridge were unsuccessful; therefore, the introduction of the methyl group was carried out after the oxidation of hemiacetal group to the lactone.
Authors: Liliya Kh. Faizullina*, Yuliya А. Khalilova, Shamil M. Salikhov, Farid A. Valeev