Hydrolytic enantioselective protonation of dienyl esters and a beta-diketone catalyzed by phase-transfer catalysts are described. The latter reaction is the first example of an enantio-convergent retro-Claisen condensation. Corresponding various optically active alpha,beta-unsaturated ketones having tertiary chiral centers adjacent to carbonyl groups were obtained in good to excellent yields and enantiomeric ratios (83-99%, up to 97.5:2.5 er).
The efficient synthesis of substituted 2-methylbenzofurans
作者:Sergei G. Mikhalyonok、Aliaxandr S. Arol、Dmitri A. Litvinau、Nina M. Kuz’menok、Vladimir S. Bezborodov
DOI:10.1007/s10593-019-02443-3
日期:2019.3
The efficientsynthesis of substituted 2-methylbenzofurans by aromatization of accessible allyl-substituted cyclohex-2-enones in the presence of iodine followed by dehydroiodination of the 2-iodomethyl-2,3-dihydrobenzofuran intermediate is described.