Abstract

Asymmetric catalysis has evolved arguably into the most powerful method for the synthesis of enantioenriched molecules.1 It features high efficiency and atom-economy in principle as compared to other approaches such as chiral resolution and auxiliary-based asymmetric synthesis, thereby enabling increasing applications in industrial synthesis.2 In the past few decades, a wide range of chiral catalytic systems with diverse activation modes have been developed. However, the basis for asymmetric induction is largely limited to spatial interaction between substrate and catalyst. Asymmetric discrimination between two sterically similar groups without a directing group or electronic manipulation remains challenging. Here we address this formidable challenge by introducing a robust organocatalytic system leading to excellent enantioselectivity between aryl and heteroaryl groups.3 With the versatile 2-indole imine methide as platform, an excellent combin

ation of a superb chiral phosphoric acid and the optimal hydride source provided efficient access to a range of highly enantioenriched indole-containing triarylmethanes. More details of this process will be presented. 

Reference:

1. 1. E. N. Jacobsen, A. Pfaltz, H. Yamamoto, Comprehensive Asymmetric Catalysis I−III, Springer, Berlin, 1999.
   2. H. U. Blaser, H.-J. Federsel, Asymmetric Catalysis on Industrial Scale: Challenges, Approaches, and Solutions, Wiley-VCH, 2010.

• Q. L. Yan, M. Duan, C. E. Chen, Z. Q. Deng, M. D. Wu, P. Y. Yu, M.-L. He, G. Y. Zhu, K. N. Houk, J. W. Sun, Chem. Sci., 2022,13, 5767-5773.