CHIBACHA - Chiral Base C-H Activation

The goal of this proposal is to develop a new strategy for asymmetric C(sp3)−H activation using a chiral base instead of chiral ligand, and will focus on oxidative addition-induced and decarboxylation-induced reactions. Using this new strategy, a wide range of representative and valuable chiral four-membered (hetero)cyclic and five-membered (hetero)cyclic organic molecules will be synthesized. Typical chiral Br¢nsted acids and the designed ionic liquid-functionalized chiral phosphoric acids will be prepared by using commercially available raw materials. They will be tested in the two proposed concepts. In the case of oxidative addition-induced reactions, some feasible examples aiming at synthesizing chiral indanes, indolines, dihydrobenzofurans, benzocyclobutenes, and lactams will be developed from readily available aryl or alkenyl halides or triflates. For the decarboxylation-induced reactions, a racemic version will be first developed. Then, the chiral base concept will be applied in the synthesis of chiral benzocyclobutenes, indanes, indolines, and dihydrobenzofurans. In each of the reactions involved, some key reaction parameters including chiral acid, ligand, solvent, base, reaction temperature as well as the structural features of the substrates will be studied. In addition, recyclable ionic liquid-functionalized chiral Br¢nsted acids and the effect of traditional ionic liquids as the additives or solvents will be first studied in enantioselective C(sp3)−H bond activation. In order to get a clear understanding on the nature of the asymmetric induction during the catalytic cycle, computational studies will also be performed using DFT methods. The applicant's previous research experience in C−H activation, ionic liquids catalysis and asymmetric catalysis areas will benefit the project. The project will foster mutually beneficial research collaboration in Europe in the field of C−H activation and green chemistry.