Chem Commun (Camb)
School of Chemistry and Advance Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Hyderabad-500046, India.
Published: August 2015
We report the regiospecific synthesis of the first chloro-substituted porphycenes as two positional isomers of β-tetrachlorotetramethoxyporphycene. The positional effect of the substituents on these isomers could be clearly distinguished in their structure and photophysical properties.
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http://dx.doi.org/10.1039/c5cc03867g | DOI Listing |
J Am Chem Soc
January 2025
Molecular Synthesis Center, Key Laboratory of Marine Drugs of Ministry of Education, Shandong Key Laboratory of Glycoscience and Glycotherapeutics, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
2-Deoxy-β-glycosides are essential components of natural products and pharmaceuticals; however, the corresponding 2-deoxy-β-glycosidic bonds are challenging to chemically construct. Herein, we describe an efficient catalytic protocol for synthesizing 2-deoxy-β-glycosides via either IPrAuNTf-catalyzed activation of a unique 1,2--positioned C2--propargyl xanthate (OSPX) leaving group or (PhO)PAuNTf-catalyzed activation of a 1,2--C2--alkynylbenzoate (OABz) substituent of the corresponding thioglycosides. These activation processes trigger 1,2-alkyl/arylthio-migration glycosylation, enabling the synthesis of structurally diverse 2-deoxy-β-glycosides under mild reaction conditions.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States.
Enthalpy is often the focal point when designing monomers for polymer circularity, but much less is explored on how entropy can be exploited to create polymers with synergistic circularity and properties. Here, we design a series of spiro-lactones (SLs) with closed-chain cycloalk(en)yl substituents at the α,α-position of δ-valerolactone (δVL), which, when combined with the parent δVL and -α,α-dialkyl-substituted δVL with open-chain alkyl groups, provide a desired platform for exploring the circular polymer design by focusing on the entropy change of polymerization. These SLs exhibit finely balanced (de)polymerizability that is regulated chiefly by entropy differentiation, allowing both the facile synthesis of polyester PSLs ( up to 1000 kg mol) in a living fashion and selective depolymerization of the PSLs to completely recover monomers under mild conditions (using a recyclable catalyst at 100 °C).
View Article and Find Full Text PDFIUCrJ
March 2025
Department of Chemistry, Università degli Studi di Milano, via Golgi 19, 20133 Milano, Italy.
A detailed study of the X...
View Article and Find Full Text PDFChemphyschem
January 2025
Utah State University, Department of Chemistry and Biochemistry, 0300 Old Main Hill, 84322-0300, Logan, UNITED STATES OF AMERICA.
A halobenzene molecule contains several sites that are capable of acting in an electron-donating capacity within a H-bond. One set of such sites comprise the lone electron pairs of the halogen (X) atoms on the periphery of the ring. The π-electron system above the ring plane can also fulfill this function in many cases.
View Article and Find Full Text PDFDalton Trans
January 2025
Chongqing Key Laboratory of Green Catalysis Materials and Technology, College of Chemistry, Chongqing Normal University, Chongqing 401331, China.
A deeper understanding of the mechanisms underlying transition metal-catalyzed transformation is crucial for developing innovative strategies to synthesize chiral organoselenium compounds. In this study, we developed and investigated a three-layer chirality relay model for the rhodium-catalyzed asymmetric hydroselenation of alkenes through density functional theory (DFT) calculations. In the back layer of this model, the four bulky substituents on the phosphorus atom of the bidentate chiral MeO-BIPHEP ligand were positioned on axial and equatorial bonds, thereby influencing the configuration of the middle layer.
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