An achiral oligo(p-phenylene vinylene) derivative with a ureido-triazine hydrogen bonding unit self-assembles into rows of hydrogen bonded dimers at the liquid/solid interface. Scanning tunneling microscopy reveals the formation of chiral domains, but overall, the surface remains racemic. Addition of a chiral auxiliary which is able to interact with the dimers through hydrogen bonding, showed that global organizational chirality could be achieved since a majority of the domains show the same handedness. After removing the chiral auxiliary with a volatile solvent, the global organizational chirality could be trapped, revealing a memory effect. With this straightforward supramolecular approach, we were able to create a chiral surface with preferred handedness composed of achiral molecules at the air/solid interface.
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http://dx.doi.org/10.1021/ja2106652 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Shanghai Jiao Tong University, Frontiers Science Center for Transformative Molecules, 800 Dongchuan Road, 200240, Shanghai, CHINA.
Along with the renaissance of radical chemistry, the past decade has witnessed rapid development in radical-mediated rearrangement reactions. A wide diversity of radical approaches harnessing functional-group migration (FGM) have been devised to enhance both synthetic efficiency and molecular complexity. However, the application of FGM reactions to construct stereogenic centers remains underexplored owing to the inherent challenges of asymmetric radical reactions.
View Article and Find Full Text PDFJ Org Chem
January 2025
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, 15 Yu Cai Road, Guilin 541004, China.
A cascade reaction of Pd(II)/dppben-catalyzed [3 + 2] cycloaddition of -aryl nitrones with allenoates and sequential reduction has been developed for the synthesis of functionalized benzazepines bearing three contiguous carbon stereocenters in moderate to good yields ranging from 15 to 82% and high diastereoselectivity. The obtained benzazepines could be converted into various benzazepine scaffolds, and an estrone-derived benzazepine scaffold was prepared over four steps from estrone. More importantly, chiral benzazepine bearing three contiguous carbon stereocenters could be obtained in 88% ee value with chiral auxiliary.
View Article and Find Full Text PDFMar Drugs
January 2025
Organic Chemistry, Saarland University, Campus Building C4.2, D-66123 Saarbruecken, Germany.
Matteson homologation, a successive extension of chiral boronic esters, is perfectly suited for the synthesis of complex molecular structures containing several stereogenic centers. The "classical version" allows the introduction of various functional groups in a 1,2--configuration. The absolute configuration is determined by the choice of the chiral auxiliary, which can be used to introduce several stereogenic centers.
View Article and Find Full Text PDFChirality
February 2025
Department of Chemistry, Bogazici University, Istanbul, Turkey.
2-Thiohydantoin derivatives, including different substitutions at N-1 and C-5 (5-methyl-, 5-isopropyl-, 1-acetyl-5-methyl-, and 1-acetyl-5-isopropyl-) (1-4, respectively), were synthesized by the known literature methods. In these synthetic pathways, it was reported that enantiomerically pure 2-thiohydantions were obtained in the absence of any solvent via the reaction of L-amino acids with thiourea (1&2) and via the reaction of L-amino acids with NHSCN and acetic anhydride (3&4). However, in this study, in contrary to the previous literature studies, racemic mixtures of 2-thiohydantoins were obtained although the same synthetic methods were used.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
ConspectusChiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes.
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