142975-31-3Relevant articles and documents
Steroidal guanidinium receptors for the enantioselective recognition of N-acyl α-amino acids
Davis, Anthony P.,Lawless, Laurence J.
, p. 9 - 10 (1999)
Guanidinium cations 4 and 5 extract N-acetyl α-amino acids into CHCl3 from an aqueous medium with enantiomeric excesses of up to 80%.
Influence of Conformational Change and Interligand Hydrogen Bonding in a Chiral Metal-Organic Cage
Sen, Shovan Kumar,Natarajan, Ramalingam
, p. 7180 - 7188 (2019)
We report about the coordination-driven self-assembly of a chiral bis-pyridyl ligand (1), synthesized from steroidal cholic acid, with Pd(II) ions to form a chiral metal-organic Pd2(1)4 cage. The self-assembly of the cage was facilitated by favorable conformational change in the alkyl chain of the cholic acid. Interligand hydrogen bonding played a crucial role in directing the formation of a C4 symmetric cage among different possible isomers, as suggested by DFT studies, and control experiments with different ligands.
Improving reactivity and selectivity of aqueous-based Heck reactions by the local hydrophobicity of phosphine ligands
Roberts, Gina M.,Zhang, Shiyong,Zhao, Yan,Woo, L. Keith
, p. 8263 - 8270 (2015/10/05)
Modification of a triarylphosphine with a cholate moiety affords a new ligand, 1, which is effective in palladium-catalyzed Heck cross-couplings between acrylates and aryl iodides under mild, aqueous reaction conditions. High yields, up to 99%, were achieved in water at 40 °C. In competition studies, a more hydrophobic substrate (n-Bu acrylate) was preferred over the least hydrophobic substrate (methyl acrylate), supportive of a localized hydrophobic microenvironment near the catalytic center. The enhanced reactivity and selectivity for hydrophobic substrates disappeared when the local hydrophobicity was eliminated using a standard water-soluble phosphine or in organic solvents.
