Development of <i>C</i><sub>2</sub>-Symmetric Chiral Spirocyclic Phase-Transfer Catalysts: Synthesis and Application to Asymmetric Alkylation of Glycinate Schiff Base
Changming Xu, Yinsheng Qi, Xinshuang Yang, Xiangfan Li, Zhenpeng Li, Lei Bai
Abstract
A class of C2-symmetric chiral spirocyclic phase-transfer catalysts based on tetramethyl-1,1′-spirobiindane scaffold was synthesized from commercially available bisphenol A in 12 steps with 22–25% total yields, which features a more rigid and stable backbone and smaller dihedral angles and can be easily modified. These catalysts show high catalytic performance in the asymmetric alkylation of tert-butyl glycinate Schiff base at only 2 mol % catalyst loading, giving the target products with up to 92% yield and 98% ee.
Topics & Concepts
ChemistryCatalysisAlkylationSchiff baseYield (engineering)Phase (matter)Dihedral angleBase (topology)Enantioselective synthesisCombinatorial chemistryMedicinal chemistryPolymer chemistryOrganic chemistryMoleculeHydrogen bondMathematical analysisMathematicsMetallurgyMaterials scienceAxial and Atropisomeric Chirality SynthesisAsymmetric Synthesis and CatalysisSynthesis of Indole Derivatives