[reaction: see text] Peptides containing a secondary amine and a carboxylic acid in a specific orientation to each other are presented as highly efficient catalysts for asymmetric aldol reactions: (1) their activity is considerably higher compared to that of proline, and (2) the enantioselectivity of the peptidic catalysts can be changed from (R)- to (S)-selectivity by simple modifications of the secondary structure.
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http://dx.doi.org/10.1021/ol0500259 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
Carboranyl amines are distinct from typical organic amines. Due to the electronic influence of the carborane cage, they have low nucleophilicity and are reluctant to alkylate. Moreover, asymmetric synthesis of chiral carboranes is still in its infancy.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Ni-catalyzed asymmetric reductive cross-coupling reactions provide rapid and modular access to enantioenriched building blocks from simple electrophile precursors. Reductive coupling reactions that can diverge through a common organometallic intermediate to two distinct families of enantioenriched products are particularly versatile but underdeveloped. Here, we describe the development of a bis(oxazoline) ligand that enables the desymmetrization of -anhydrides.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The University of Hong Kong, Hong Kong Island 000000, Hong Kong SAR, China.
Methanol (ME) is a liquid hydrogen carrier, ideal for on-site-on-demand H generation, avoiding its costly and risky distribution issues, but this "ME-to-H" electric conversion suffers from high voltage (energy consumption) and competitive oxygen evolution reaction. Herein, we demonstrate that a synergistic cofunctional PtPd/(Ni,Co)(OH) catalyst with Pt single atoms (Pt) and Pd nanoclusters (Pd) anchored on OH-vacancy(V)-rich (Ni,Co)(OH) nanoparticles create synergistic triadic active sites, allowing for methanol-enhanced low-voltage H generation. For MOR, OH* is preferentially adsorbed on Pd and then interacts with the intermediates (such as *CHO or *CHOOH) adsorbed favorably on neighboring Pt with the assistance of hydrogen bonding from the surface hydrogen of (Ni,Co)(OH).
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
State Key Laboratory for Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education and College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
The cobalt-nitrogen-carbon (Co─N─C) single-atom catalysts (SACs) are promising alternatives to precious metals for catalyzing the hydrogen evolution reaction (HER) and their activity is highly dependent on the coordination environments of the metal centers. Herein, a NaHCO etching strategy is developed to introduce abundant in-plane pores within the carbon substrates that further enable the construction of low-coordinated and asymmetric Co─N sites with nearby vacancy defects in a Co─N─C catalyst. This catalyst exhibits a high HER activity with an overpotential (η) of merely 78 mV to deliver a current density of 10 mA cm, a Tafel slope of 45.
View Article and Find Full Text PDFAcc Chem Res
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, and Discipline of Intelligent Instrument and Equipment, Xiamen University, Xiamen 361005, P. R. China.
ConspectusMolecular photoelectrocatalysis, which combines the merits of photocatalysis and organic electrosynthesis, including their green attributes and capacity to offer novel reactivity and selectivity, represents an emerging field in organic chemistry that addresses the growing demands for environmental sustainability and synthetic efficiency. This synergistic approach permits access to a wider range of redox potentials, facilitates redox transformations under gentler electrode potentials, and decreases the use of external harsh redox reagents. Despite these potential advantages, this area did not receive significant attention until 2019, when we and others reported the first examples of modern molecular photoelectrocatalysis.
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