α‐Amino‐ iso ‐Butyric Acid Foldamers Terminated with Rhodium(I) N‐Heterocyclic Carbene Catalysts

Autor: David P. Tilly, William Cullen, Heng Zhong, Romain Jamagne, Inigo Vitórica‐Yrezábal, Simon J. Webb
Rok vydání: 2022
Předmět:
Zdroj: Tilly, D P, Cullen, W, Zhong, H, Jamagne, R, Vitórica-yrezábal, I & Webb, S J 2022, ' α-Amino-iso-Butyric Acid Foldamers Terminated with Rhodium(I) N-Heterocyclic Carbene Catalysts ', Chemistry – A European Journal . https://doi.org/10.1002/chem.202104293
ISSN: 1521-3765
0947-6539
Popis: To investigate how remotely induced changes in ligand folding might affect catalysis by organometallic complexes, dynamic α-amino-iso-butyric acid (Aib) peptide foldamers bearing rhodium(I) N-heterocyclic carbene (NHC) complexes have been synthesised and studied. X-ray crystallography of a foldamer with an N-terminal azide and a C-terminal Rh(NHC)(Cl)(diene) complex showed a racemate with a chiral axis in the Rh(NHC) complex and a distorted 310 helical body. Replacing the azide with either one or two chiral Lα-methylvaline (L-αMeVal) residues gave diastereoisomeric foldamers that each possessed point, helical and axial chirality. NMR spectroscopy revealed an unequal ratio of diastereoisomers for some foldamers, indicating that the chiral conformational preference of the N-terminal residue(s) was relayed down the 1 nm helical body to the axially chiral Rh(NHC) complex. Although the remote chiral residue(s) did not affect the stereoselectivity of hydrosilylation reactions catalysed by these foldamers, these studies suggest a potential pathway towards remote conformational control of organometallic catalysts.
Databáze: OpenAIRE
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