Lewis acid mediated (3 + 2) cycloadditions of donor-acceptor cyclopropanes with heterocumulenes.

Org Lett

The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC 101-20, Pasadena, California 91125, USA.

Published: October 2012

Isocyanates, isothiocyanates, and carbodiimides are effective substrates in (3 + 2) cycloadditions with donor-acceptor cyclopropanes for the synthesis of five-membered heterocycles. These reactions exhibit a broad substrate scope, high yields, and well-defined chemoselectivity. Discussed herein are the implications of Lewis acid choice on the stereochemical outcome and the reaction mechanism.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3490221PMC
http://dx.doi.org/10.1021/ol302494nDOI Listing

Publication Analysis

Top Keywords

lewis acid
8
cycloadditions donor-acceptor
8
donor-acceptor cyclopropanes
8
acid mediated
4
mediated cycloadditions
4
cyclopropanes heterocumulenes
4
heterocumulenes isocyanates
4
isocyanates isothiocyanates
4
isothiocyanates carbodiimides
4
carbodiimides effective
4

Similar Publications

Entropy engineering activation of UiO-66 for boosting catalytic transfer hydrogenation.

Nat Commun

January 2025

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, 130012, Changchun, P. R. China.

High-entropy metal-organic frameworks (HE-MOFs) hold promise as versatile materials, yet current rare examples are confined to low-valence elements in the fourth period, constraining their design and optimization for diverse applications. Here, a novel high-entropy, defect-rich and small-sized (32 nm) UiO-66 (ZrHfCeSnTi HE-UiO-66) has been synthesized for the first time, leveraging increased configurational entropy to achieve high tolerance to doping with diverse metal ions. The lattice distortion of HE-UiO-66 induces high exposure of metal nodes to create coordination unsaturated metal sites with a concentration of 322.

View Article and Find Full Text PDF

Carbocation charge as an interpretable descriptor for the catalytic activity of hydrolytic nanozymes.

J Colloid Interface Sci

December 2024

College of Materials Science and Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao, Shandong 266042, China; Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, MOE, Shandong Key Laboratory of Biochemical Analysis, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao, Shandong 266042, China. Electronic address:

A universal theory for predicting the catalytic activity of hydrolytic nanozymes has yet to be developed. Herein, by investigating the polarization and hydrolysis mechanisms of nanomaterials towards amide bonds, carbocation charge was identified as a key electronic descriptor for predicting catalytic activity in amide hydrolysis. Through machine learning correlation analysis and the Sure Independence Screening and Sparsifying Operator (SISSO) algorithm, this descriptor was interpreted to associate with the d-band center and Lewis acidity on the nanomaterial surface.

View Article and Find Full Text PDF

Oxygen vacancy-rich defective tungsten oxide (WO) modified by Prussian blue for efficient photocatalytic carbon dioxide conversion and tetracycline degradation.

J Colloid Interface Sci

December 2024

Laboratory of Alternative Energy Conversion Systems, Department of Mechanical Engineering, School of Engineering, University of Thessaly, Pedion Areos 38834, Greece. Electronic address:

The coupling of carbon dioxide (CO) with epoxides to produce cyclic carbonates is a desirable decarbonization approach, but its commercial applicability is still restricted by the costly catalysts required, as well as the need for high temperature and high pressure. Herein, oxygen vacancy-rich defective tungsten oxide (WO) rich in Lewis acid sites was modified by Prussian blue (PB), and the obtained composite reaches up to 94 % styrene carbonate yield (171 mmol gh) at ambient temperature and pressure, exhibiting outstanding advantages in the photocatalytic CO cycloaddition reaction compared with currently reported photocatalysts. It is found that the introduction of PB with photothermal properties significantly enhances the capability of WO to absorb and activate CO and epoxide, along with its light utilization ability.

View Article and Find Full Text PDF

This study presents a novel method for the efficient preparation of peptide-based films through microwave-assisted Lewis acid catalysis (MALC) of buckwheat globulin (BG). The MALC process efficiently degraded BG into small molecular peptides (1.6-1.

View Article and Find Full Text PDF

Tuning Bro̷nsted Acidity by up to 12 p Units in a Redox-Active Nanopore Lined with Multifunctional Metal Sites.

J Am Chem Soc

January 2025

Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 123 Bevier Road, Piscataway, New Jersey 08854, United States.

Electrostatic interactions, hydrogen bonding, and solvation effects can alter the free energies of ionizable functional groups in proteins and other nanoporous architectures, allowing such structures to tune acid-base chemistry to support specific functions. Herein, we expand on this theme to examine how metal sites ( = H, Zn, Co, Co) affect the p of benzoic acid guests bound in discrete porphyrin nanoprisms () in CDCN. These host-guest systems were chosen to model how porous metalloporphyrin electrocatalysts might influence H transfer processes that are needed to support important electrochemical reactions (e.

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!