Enantioselective Catalysis with Pyrrolidinyl Gold(I) Complexes: DFT and NEST Analysis of the Chiral Binding Pocket

Identifier:  imarina:9322152

Handle: https://hdl.handle.net/20.500.11797/imarina9322152

Authors:  Zuccarello, Giuseppe; Nannini, Leonardo J; Arroyo-Bondia, Ana; Fincias, Nicolas; Arranz, Isabel; Perez-Jimeno, Alba H; Peeters, Matthias; Martin-Torres, Inmaculada; Sadurni, Anna; Garcia-Vazquez, Victor; Wang, Yufei; Kirillova, Mariia S; Montesinos-Magraner, Marc; Caniparoli, Ulysse; Nunez, Gonzalo D; Maseras, Feliu; Besora, Maria; Escofet, Imma; Echavarren, Antonio M

Abstract:
A new generation of chiral gold(I) catalysts based on variations of complexes with JohnPhos-type ligands with a remote C2-symmetric 2,5-diarylpyrrolidine have been synthesized with different substitutions at the top and bottom aryl rings: from replacing the phosphine by a N-heterocyclic carbene (NHC) to increasing the steric hindrance with bis- or tris-biphenylphosphine scaffolds, or by directly attaching the C2-chiral pyrrolidine in the ortho-position of the dialkylphenyl phosphine. The new chiral gold(I) catalysts have been tested in the intramolecular [4+2] cycloaddition of arylalkynes with alkenes and in the atroposelective synthesis of 2-arylindoles. Interestingly, simpler catalysts with the C2-chiral pyrrolidine in the ortho-position of the dialkylphenyl phosphine led to the formation of opposite enantiomers. The chiral binding pockets of the new catalysts have been analyzed by DFT calculations. As revealed by non-covalent interaction plots, attractive non-covalent interactions between substrates and catalysts direct specific enantioselective folding. Furthermore, we have introduced the open-source tool NEST, specifically designed to account for steric effects in cylindrical-shaped complexes, which allows predicting experimental enantioselectivities in our systems.© 2023 The Authors. Published by American Chemical Society.