Diastereoselective Synthesis of Trifluoromethylated γ-Butyrolactonesvia N-Heterocyclic Carbene-Catalyzed Conjugated Umpolung of α,β-Unsaturated Aldehydes
作者:Keiichi Hirano、Isabel Piel、Frank Glorius
DOI:10.1002/adsc.200800051
日期:2008.5.5
The N-heterocyclic carbene-catalyzed conjugate umpolung of differently substituted α,β-unsaturated aldehydes is described. Coupling of these compounds with a variety of trifluoromethylated ketones results in the selective formation of fluorinated γ-butyrolactones. Using thiazolium-derived N-heterocyclic carbenes, the unlike stereoisomers are formed predominantly, whereas the imidazol-2-ylidene IMes
描述了不同取代的α,β-不饱和醛的N-杂环卡宾催化的共轭物质。这些化合物与各种三氟甲基化的酮的偶联导致氟化γ-丁内酯的选择性形成。使用源自噻唑鎓的N-杂环卡宾,主要形成不同的立体异构体,而咪唑-2-亚基IMes导致较低的选择性和类似异构体的优选形成。