A5059815748- Asymmetric Synthesis and Catalysis
- Synthetic Organic Chemistry Methods
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Chemical synthesis and alkaloids
- Asymmetric Hydrogenation and Catalysis
- Microbial Natural Products and Biosynthesis
- Cyclopropane Reaction Mechanisms
- Alkaloids: synthesis and pharmacology
- Chemical Synthesis and Analysis
- Advanced Synthetic Organic Chemistry
- HIV/AIDS drug development and treatment
- Traditional and Medicinal Uses of Annonaceae
- Catalytic C–H Functionalization Methods
- Internet Traffic Analysis and Secure E-voting
- Plant biochemistry and biosynthesis
- Marine Sponges and Natural Products
- Network Traffic and Congestion Control
- Crystallography and molecular interactions
- Pharmacogenetics and Drug Metabolism
- Ion Channels and Receptors
- HIV-related health complications and treatments
- Software-Defined Networks and 5G
- Veterinary medicine and infectious diseases
- Artificial Intelligence in Healthcare and Education
College of New Jersey
2023
Tsinghua University
2022-2023
P S Jones Middle School
2023
University of California, Irvine
2015-2022
California Institute of Technology
2008-2016
Gilead Sciences (United States)
2010-2013
Division of Chemistry
2011
University of California, Berkeley
2007
All-carbon quaternary stereocenters have posed significant challenges in the synthesis of complex natural products. These important structural motifs inspired development broadly applicable palladium-catalyzed asymmetric allylic alkylation reactions unstabilized non-biased enolates for enantioenriched α-quaternary This microreview outlines key considerations application and presents recent total syntheses products that employed these powerful transformations direct, catalytic,...
Cobicistat (3, GS-9350) is a newly discovered, potent, and selective inhibitor of human cytochrome P450 3A (CYP3A) enzymes. In contrast to ritonavir, 3 devoid anti-HIV activity thus more suitable for use in boosting drugs without risking selection potential drug-resistant HIV variants. Compound shows reduced liability drug interactions may have improvements tolerability over ritonavir. addition, has high aqueous solubility can be readily coformulated with other agents.
A catalytic, enantioselective γ-alkylation of α,β-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- iridium-catalyzed α-alkylation an extended enolate, subsequent translocation chirality to the γ-position via Cope rearrangement.
An N-oxide fragmentation/hydroxylamine oxidation/intramolecular 1,3-dipolar cycloaddition cascade efficiently converted an oxidized congener of akuammicine into the complex, hexacyclic architecture alsmaphorazine alkaloids. This dramatic structural change shows chemical feasibility our novel proposal for biogenesis. Critical to these endeavors was a marked improvement in previously reported Zincke aldehyde approach indole alkaloids, which permitted gram-scale synthesis akuammicine. The...
Contraction action! A simple protocol for the catalytic asymmetric synthesis of highly functionalized γ-quaternary acylcyclopentenes (see schematic) in up to 91 % overall yield and 92 ee has been developed. The reaction sequence employs a palladium-catalyzed enantioselective alkylation exploits unusual stability β-hydroxy cycloheptanones achieve general robust method performing two-carbon ring contractions. Detailed facts importance specialist readers are published as "Supporting...
When epi isn't! The first total synthesis of the reported structures 9-epi-presilphiperfolan-1-ol and presilphiperfolan-1-ol has been achieved. Key steps are a catalytic asymmetric alkylation novel diene-containing electrophile followed by two-carbon ring contraction an intramolecular Diels–Alder cycloaddition to form stereochemically dense tricyclic core. synthetic work resulted in structural revision (see scheme).
A general method for the synthesis of β-substituted and unsubstituted cycloheptenones bearing enantioenriched all-carbon γ-quaternary stereocenters is reported. Hydride or organometallic addition to a seven-membered ring vinylogous ester followed by finely tuned quenching parameters achieves elimination corresponding cycloheptenone. The resulting enones are elaborated bi- tricyclic compounds with potential preparation non-natural analogs whose structures embedded in number cycloheptanoid...
We report herein an efficient, stereocontrolled, and chromatography-free synthesis of the novel broad spectrum antibiotic GDC-5338. The route features construction a functionalized tripeptide backbone, high-yielding macrocyclization via Pd-catalyzed Suzuki-Miyaura reaction, late-stage elaboration key amide bonds with minimal stereochemical erosion. Through extensive reaction development analytical understanding, these advancements allowed preparation GDC-5338 in 17 steps, 15% overall yield,...
Wenn epi doch nicht ist! Die erste Totalsynthese der beschriebenen Strukturen von 9-epi-Presilphiperfolan-1-ol und Presilphiperfolan-1-ol wurde abgeschlossen. Schlüsselschritte sind die katalytische asymmetrische Alkylierung eines neuartigen Dien-Elektrophils mit anschließender C2-Ringkontraktion eine intramolekulare Diels-Alder-Cycloaddition zur Bildung des dichten tricyclischen Kerns. Synthesestudie führt Strukturrevision Presilphiperfolan-1-ols (siehe Schema).
Ein einfaches Protokoll für die katalytische asymmetrische Synthese von hoch funktionalisierten γ-quartären Acylcyclopentenen (siehe Schema) mit bis zu 91 % Gesamtausbeute und 92 ee wurde entwickelt. Die Reaktionssequenz enthält eine Palladium-katalysierte enantioselektive Alkylierung nutzt ungewöhnliche Stabilität β-Hydroxycycloheptanonen allgemeine robuste Methode zur Ringverengung um zwei Kohlenstoffatome. Detailed facts of importance to specialist readers are published as ”Supporting...
We report a fit-for-purpose, stereocontrolled, and chromatography-free first-generation manufacturing process for GDC-6599 (1), TRPA1 inhibitor, to enable first-in-human clinical trials. Key steps in the include consecutive KRED-mediated asymmetric ketone reductions, nucleophilic cyanation, 1,2,4-oxadiazole formation, late stage purinone N-alkylation. The 13-step successfully produced 4.39 kg of (1) 11% overall yield with 99.6 A% HPLC purity, >99.9:0.1 er, dr.
Abstract Presilphiperfolanole bilden eine biosynthetisch bedeutende Klasse von Sesquiterpenen, die sich zu verschiedenen weiteren Sesquiterpen‐Grundgerüsten umlagern können. Ihr Ursprung lässt auf einfache lineare Terpenvorstufen zurückverfolgen. Durch umfassende biochemische, theoretische und synthetische Arbeiten gelang es, ein mechanistisches Verständnis für enzymatische Cyclisierung gewinnen. Um ungewöhnliche bemerkenswerte Grundstruktur der synthetisch erhalten, wurde ebenfalls intensiv...
The construction of arene-fused cyclic β-ketoesters from 2-iodoaryl esters and 1,1-cyclopropane diesters is detailed. synthetic method takes advantage a CuI·SMe2-mediated homoconjugate addition followed by decarboxylative Dieckmann cyclization to afford valuable polycyclic building blocks. Various iodoaryl were evaluated, the limitations both reactions are discussed. Several mechanistic probes detailed applications described.
We offer a new biogenetic proposal for the origin of complex alkaloid alstonlarsine A, through rearrangement Strychnos alkaloids alstolucines B and F. Further, we provide evidence chemical feasibility this in facile conversion synthetic into A short, efficient sequence N-methylation, β-elimination, cascade 1,7-hydride shift/Mannich cyclization. believe that is first involving "tert-amino effect", hydride-shift-based internal redox trigger Mannich further interesting feature its...
Predicting the geographical location of an IP host is a fundamental and valuable but long-standing challenge in field network research. Although delay-based methods have relatively high coverage low time consumption, currently this type method not accurate enough requires large number vantage points, making its cost high. In paper, we propose novel framework to make geolocation more cheap. Firstly, collect 373 Looking Glass with known addresses overcome problem by using them as points....
The synthesis of annulated tetrasubstituted furans using diazoallene precursors is described. This reaction provides efficient access to synthetically useful furan intermediates, which are otherwise difficult obtain.
Die Autoren dieser Zuschrift haben versehentlich die falsche Bezeichnung “9β-presilphiperfolan-1α-ol” für den von König und Leitão isolierten Naturstoff angegeben. Der korrekte Name sollte “9β-presilphiperfolan-1β-ol” lauten, um der relativen syn-Anordnung Hydroxy- zu C9-Methylgruppe im gerecht werden. Dieser Fehler findet sich Inhaltsverzeichnisbild sowie in Teilen des Texts Hintergrundinformationen.
In recent years, the field of Natural Language Processing (NLP) has witnessed a groundbreaking transformation with emergence large language models (LLMs). ChatGPT stands out as an example among these LLM captivating considerable public interest due to its impressive generation capabilities. Researchers have been exploring potential using for data annotation tasks, aiming discover more timesaving and cost-effective approaches. this paper, we present comprehensive evaluation ChatGPT's...