Non-biaryl atropisomers are valuable in medicine, materials, and catalysis, but their enantioselective synthesis remains a challenge. Herein, a counterion-mediated O-alkylation method for the generation of atropisomeric amides with an er up to 99:1 is outlined. This dynamic kinetic resolution is enabled by the observation that the rate of racemization of atropisomeric naphthamides is significantly increased by the presence of an intramolecular O-H⋅⋅⋅NCO hydrogen bond. Upon O-alkylation of the H-bond donor, the barrier to rotation is significantly increased. Quantum calculations demonstrate that the intramolecular H-bond reduces the rotational barrier about the aryl-amide bond, stabilizing the planar transition state for racemization by approximately 40 kJ mol , thereby facilitating the observed dynamic kinetic resolution.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6492105PMC
http://dx.doi.org/10.1002/anie.201814362DOI Listing

Publication Analysis

Top Keywords

dynamic kinetic
12
kinetic resolution
12
hydrogen-bond-enabled dynamic
4
resolution axially
4
axially chiral
4
chiral amides
4
amides mediated
4
mediated chiral
4
chiral counterion
4
counterion non-biaryl
4

Similar Publications

Dissolution of CO in water followed by the subsequent hydrolysis reactions is of great importance to the global carbon cycle, and carbon capture and storage. Despite numerous previous studies, the reactions are still not fully understood at the atomistic scale. Here, we combined ab initio molecular dynamics (AIMD) simulations with Markov state models to elucidate the reaction mechanisms and kinetics of CO in supercritical water both in the bulk and nanoconfined states.

View Article and Find Full Text PDF

Effects of kinesio taping on lower limb biomechanical characteristics during dynamic postural control tasks in individuals with chronic ankle instability.

PLoS One

January 2025

Key Laboratory of Sports Engineering of General Administration of Sport of China, Wuhan Sports University, Wuhan, Hubei Province, China.

Purpose: Previous studies have demonstrated significant biomechanical differences between individuals with chronic ankle instability (CAI) and healthy controls during the Y-balance test. This study aimed to examine the effects of kinesio taping (KT) on lower limb biomechanical characteristics during the Y-balance anterior reach task in individuals with CAI.

Methods: A total of 30 participants were recruited, comprising 15 individuals with CAI and 15 healthy controls.

View Article and Find Full Text PDF

Heterojunctions, known for their decent separation of photo-generated electrons and holes, are promising for photocatalytic CO reduction. However, a significant obstacle in traditional post-assembled heterojunctions is the high interfacial barrier for charge transfer caused by atomic lattice mismatch at multiphase interfaces. Here, as research prototypes, the study creates a lattice-matched co-atomic interface within CsPbBr-CsPbBr polytypic nanocrystals (113-125 PNs) through the proposed in situ hybrid strategy to elucidate the underlying charge transfer mechanism within this unique interface.

View Article and Find Full Text PDF

Chimeric antigen receptor T cells (CART) targeting CD19 through CD28.ζ signaling induce rapid lysis of leukemic blasts, contrasting with persistent tumor control exhibited by 4-1BB.ζ-CART.

View Article and Find Full Text PDF

Unlabelled: The tonsils have been identified as a site of replication for Epstein-Barr virus, adenovirus, human papillomavirus, and other respiratory viruses. Human tonsil epithelial cells (HTECs) are a heterogeneous group of actively differentiating cells. Here, we investigated the cellular features and susceptibility of differentiated HTECs to specific influenza viruses, including expression of avian-type and mammalian-type sialic acid (SA) receptors, viral replication dynamics, and the associated cytokine secretion profiles.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!