Reversal of Enantioselectivity by Tuning the Conformational Flexibility of Phase-Transfer Catalysts

摘要

Catalytic asymmetric synthesis provides one of the most powerful and economical approaches for the preparation of a variety of enantiomerically enriched compounds that are critical to developments in medicine, biology, and materials science. In this scenario, the development of environmentally friendly, highly efficient, and selective chiral catalysts is important. Therefore, one crucial objective is the design and synthesis of new chiral catalysts, which enable challenging and/or previously unknown asymmetric transformations to occur in a highly efficient way. The requirement of maximum conformational rigidity is central to the design of a chiral catalyst. The rigid structure of the catalyst would enhance the enantiofacial differentiation by minimizing the possibilities of different conformers available to the coupling partners, and thus, deliver the maximum asymmetric induction from the chiral catalyst.