Study On Allylation Of Indole Ketone Compounds

The 3,3’-disubstituted oxindole derivatives are important heterocyclic motifs often found in many biologically active natural products and pharmaceutically compounds. So far, many remarkable endeavours have been made to develop general and efficient methods for the synthesis of such compounds. This thesis is concerned with the studies on the construction of 3,3’-disubstituted oxindoles containing quaternary carbon center by a new allylation. It consists of the following three parts:Chapter Ⅰ:A review of literature on the construction of quaternary carbon centers by allylic alkylation strategy using several common allyl reagents, and the progress in the synthesis of 3,3’-substituted oxindoles.Chapter Ⅱ:Allyl trichloroacetimidate has been widely used as a reagent for the O-allylation of alcohols under acidic conditions. Studies on the C-allylation reactions using this reagent are rare. On the other hand, the allylic alkylation of 3-substituted oxindoles are performed at the basic or neutral conditions. We first present Lewis acid catalyzed allylic alkylation of 3-substiruted oxindoles by employing allyl trichloroacetimidate as the electrophile. After screening reaction conditions, we found that using BF3-Et2O as catalyst, CH2Cl2 as the solvent, and addition of 3.0 equiv of allyl trichloroacetimidate by 6 times at room temperature to be the optimal conditions.Chapter Ⅲ:In chapter 3, analysis of the mechanism on the asymmetric allylation of the 3-substituted oxindoles revealed that the stereocontrolled electrophile reagents play important roles in enantioinduction. We envisage that a sterocontrolled nucleophile may also give enantioselectivity. Thus, strategies combining cinchona-based organocatalysts and palladium, as well as organocatalyst and Lewis acid catalyst have been attempted to realize asymmetric allylation of the 3-substituted oxindoles.