Organocatalyzed Asymmetric Synthesis of Dihydrodibenzofurans Based on a Dienamine Process
摘要:
The first organocatalyzed asymmetric method for the synthesis of dihydrodibenzofurans based on a dienamine process has been developed. This two-step protocol works with a broad range of substrates and delivers only the cis-diastereomer in good yield with up to 91% ee. The enantioenriched products have been transformed to highly functionalized and partially hydrogenated dibenzofurans in excellent diastereoselectivities.
Electronically unfavorable addition of electron-deficient olefins to isochromenylium tetrafluoroborates initiated by C-1 O-glycosylation
作者:Shu-Yan Yu、Zhi-Long Hu、Hao Zhang、Shaozhong Wang、Zhu-Jun Yao
DOI:10.1016/j.tetlet.2012.03.106
日期:2012.5
and electron-deficient olefins have been studied and achieved by assistance of a phenolic hydroxyl group in the olefin substrates, providing the corresponding 2-oxabicyclo[3.3.1]nonane derivatives diastereoselectively in moderate to satisfactory yields. The new methodology is initiated by an intermolecular C-1 O-glycosylation, and completed with an intramolecular Michael addition and an aldol condensation