Tandem Cross Rauhut-Currier Cyclization Reaction And Cyclopropanation Reaction Catalyzed By Tertiary Amine

Tandem reaction (domino reaction) as an important synthetic strategy has been widely applied into the organic synthesis of natural products and biological compounds, by which complex multinuclear molecules with one or more rings could be successfully synthesized in only one step, so it shows many advantages such as high atom economy and high efficiency.Since the Rauhut-Currier reaction was firstly reported in1963, it has received much more attentions owing to its ability of generating a new C-C bond, which is one of fundamental and challenging fields in organic synthesis. However, low reactive activity and selectivity of the reaction seriously restricts its developments and extensive applications, especially in the intermolecular RC reaction between different activated alkenes.Based on our previous works, we have designed the first tandem Rauhut-Currier cyclization reaction between activated alkenes and methyl vinyl letone or acrylates, and the densely functionalized3,4-dihydropyrans was excellently obtained with high yield. While the asymmetric synthesis of the reaction was also investigated in detail, the moderate enantioselectivity was attained. Furthermore, the2-pyrone derivatives, generated from the approach catalyzed by a tertiary amine, have potential medicinal values according to the reported literatures.Herein, we also investigated the asymmetric cyclopropanation reaction of activated alkenes with y-bromo acetophenone catalyzed by tertiary amines, the cyclopropane with a chiral quaternary carbon was obtained with high yield and enantioselectivity by the method.Lastly, the highly enantioselective synthesis of fluorinated oxoindole derivatives was discussed in detail.