Using a trifluoromethylated oxazolidine (Fox) chiral auxiliary, the hydroxylation reaction of enolates was very efficiently performed under smooth and friendly conditions with molecular oxygen as oxidizer. This reaction occurred with an extremely high diastereoselectivity. After cleavage, the chiral auxiliary is efficiently recovered and highly valuable enantiopure oxygenated carboxylic acids and alcohols are released.
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http://dx.doi.org/10.1021/ol100211s | DOI Listing |
Dalton Trans
November 2024
Department of Chemistry, Durham University, South Rd, Durham, DH1 3LE, UK.
The chiral iridium rotors Ir(ppy)(pyX)Cl (X = CC-SiR, R = alkyl) remarkably contain two distinct rotational conformers in the ground (S) and excited (T) states that can be detected by NMR and emission measurements respectively at variable temperatures. The observed phosphorescent emissions, vibronic (involving L = ppy) and broad (L = pyX), arise from different triplet ligand to metal charge transfers from the two rotational conformers at distinct MLCT excited states. Both conformers exist in these Ir(ppy)(pyX)Cl rotors due to the electron-withdrawing, conjugated substituent X.
View Article and Find Full Text PDFLife (Basel)
August 2023
Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX 77058, USA.
The salt-induced peptide formation (SIPF) reaction is a prebiotically plausible mechanism for the spontaneous polymerization of amino acids into peptides on early Earth. Experimental investigations of the SIPF reaction have found that in certain conditions, the l enantiomer is more reactive than the d enantiomer, indicating its potential role in the rise of biohomochirality. Previous work hypothesized that the distortion of the CuCl active complex toward a tetrahedral-like structure increases the central chirality on the Cu ion, which amplifies the inherent parity-violating energy differences between l- and d-amino acid enantiomers, leading to stereoselectivity.
View Article and Find Full Text PDFDalton Trans
June 2022
Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
This work presents a straightforward method for the preparation of an isoindoline bridged [M(arene)] (M = Re, Tc) -[3]arenophane. This intramolecular formation of an -complex is accompanied by the intermolecular formation of a pair of isoindoline bridged macrocyclic dinuclear sandwich complexes, one of which exhibits axial chirality.
View Article and Find Full Text PDFChem Commun (Camb)
September 2020
Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland.
Cycloruthenation is a well known process in organometallic ruthenium chemistry. In this work, we report unprecedented cycloruthenated rhenium bis-arene compounds with planar chirality. In a two-step process, the reaction of acetyl-pyridine with [Re(η6-C6H6)2]+ introduced a pyridinyl-methanol ligand at one of the arene rings.
View Article and Find Full Text PDFNature
March 2020
Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
Studies of two-dimensional electron systems in a strong magnetic field revealed the quantum Hall effect, a topological state of matter featuring a finite Chern number C and chiral edge states. Haldane later theorized that Chern insulators with integer quantum Hall effects could appear in lattice models with complex hopping parameters even at zero magnetic field. The ABC-trilayer graphene/hexagonal boron nitride (ABC-TLG/hBN) moiré superlattice provides an attractive platform with which to explore Chern insulators because it features nearly flat moiré minibands with a valley-dependent, electrically tunable Chern number.
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