Asymmetric sequential hydrogenations of α-methylene γ- or δ-keto carboxylic acids are established in one-pot using a bimetallic Ru/Ru catalyst system, achieving the stereodivergent synthesis of all four stereoisomers of both chiral γ- and δ-lactones with two non-vicinal carbon stereocenters in high yields (up to 99%) and with excellent stereoselectivities (up to >99% ee and >20:1 dr). The compatibility of the two chiral Ru catalyst systems is investigated in detail, and it is found that the basicity of the reaction system plays a key role in the sequential hydrogenation processes. The protocol can be performed on a gram-scale with a low catalyst loading (up to 11000 S/C) and the resulting products allow for many transformations, particularly for the synthesis of several key intermediates useful for the preparation of chiral drugs and natural products.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11187880 | PMC |
http://dx.doi.org/10.1002/advs.202400621 | DOI Listing |
Org Lett
January 2025
Materials Tech Laboratory for Hydrogen & Energy Storage, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, P. R. China.
A new sequential deprotonation strategy of dimethyl sulfoxide (DMSO) and propargyl alcohol in the presence of a base was developed for the generation of the α-hydroxyl carbanion, which enables rapid and controllable access to a wide range of valuable highly functionalized furans in one pot from alkynes and aldehydes under transition-metal- and additive-free conditions. Preliminary mechanistic studies revealed the crucial role of the base and DMSO. More importantly, deuterium labeling experiments confirmed the formation of the α-hydroxyl carbanion.
View Article and Find Full Text PDFColloids Surf B Biointerfaces
December 2024
Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
Significant progress has been achieved with diversity of short peptide supramolecular assemblies. However, their programmable phase modulation by single stimulus remains a great challenge. Herein, we demonstrate a dipeptide supramolecular system undergoes sequentially coupled phase transitions upon hydrogen bonding association and dissociation triggered by a single fatty acid.
View Article and Find Full Text PDFWorld J Gastrointest Surg
December 2024
Department of Critical Care Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China.
Background: Acute gastrointestinal injury (AGI) is common in intensive care unit (ICU) and worsens the prognosis of critically ill patients. The four-point grading system proposed by the European Society of Intensive Care Medicine is subjective and lacks specificity. Therefore, a more objective method is required to evaluate and determine the grade of gastrointestinal dysfunction in this patient population.
View Article and Find Full Text PDFLangmuir
December 2024
College of Textile Science and Engineering (International Institute of Silk), Zhejiang Sci-Tech University, Hangzhou 310018, China.
The active site density, intrinsic activity, and supporting substrate of cobalt phosphide catalysts are vital to their performance in alkaline water electrolysis. In this work, a CoP/CoP loaded on cellulose nanofiber-derived carbon aerogels (CP/CCAs) bifunctional electrocatalyst with a three-dimensional network and heterostructure is illustrated through sequential facile hydrothermal, freeze-drying, and phosphorylation processes. The three-dimensional network of carbon aerogels derived from cellulose nanofibers reveals a specific surface area of 183.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Artificial photosynthesis of hydrogen peroxide (HO) from ambient air, water, and sunlight has attracted considerable attention recently. Despite being extremely challenging to synthesis, sp carbon-conjugated covalent organic frameworks (COFs) can be powerful and efficient materials for the photosynthesis of HO due to desirable properties. Herein, we report the designed synthesis of an sp carbon-conjugated COF, BTD-spc-COF, from benzothiadiazole and triazine units with high crystallinity and ultralarge mesopores (∼4 nm).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!