Computational Studies on Mechanism and Stereoinduction in Asymmetric Catalysis

One of the leading goals in contemporary catalysis is to render improved efficiency to existing catalytic protocols.¹ While different forms of catalysis have witnessed tremendous success in the synthesis of complex molecules, there is minimal clarity at the mechanistic front. Further developments in the new form of catalysis/catalysts require a thorough knowledge of the reaction pathways. In asymmetric catalysis, the rationalization of selectivity is of prime importance as it paves the way for rational catalyst design. In the current talk, I will discuss the use of use of computational tools in providing a mechanistic understanding and insights into the factors controlling the stereoselectivity in a few landmark asymmetric reactions catalyzed by axially chiral catalysts/ligands. In particular, all calculations have been carried out with hybrid density functional theory (DFT) methods (B3LYP, M06, M06-2X and B3LYP-D3). The talk will focus on three forms of catalysis; 1) organocatalysis, 2) metal catalysis and, 3) cooperative catalysis. The first part encompasses the role of a newly developed class of chiral imidodiphosphoric acids in inducing selectivity in an asymmetric sulfoxidation reaction.² The second part will focus on the fine tuning of noncovalent interactions to design new phosphoramidite ligands for an asymmetric diamination reaction.³ In the last part, the role of chiral Brønsted acids when used in conjunction with Pd metal and the importance of ligand exchange in the formation of spirocyclic ring formation will be elucidated.⁴