A5023920171- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Asymmetric Synthesis and Catalysis
- Catalytic C–H Functionalization Methods
- Synthesis and Catalytic Reactions
- Asymmetric Hydrogenation and Catalysis
- Sulfur-Based Synthesis Techniques
- Oxidative Organic Chemistry Reactions
- Alkaloids: synthesis and pharmacology
- Plant and Fungal Species Descriptions
- Cyclopropane Reaction Mechanisms
- Synthetic Organic Chemistry Methods
- Chemical Synthesis and Analysis
- Axial and Atropisomeric Chirality Synthesis
- Catalytic Cross-Coupling Reactions
- Molecular spectroscopy and chirality
- Microbial Natural Products and Biosynthesis
- Vanadium and Halogenation Chemistry
- Chemical Reaction Mechanisms
Aarhus University
2019-2024
Compounds featuring atropisomerism are ubiquitous in natural products, therapeutics, advanced materials, and asymmetric synthesis. However, stereoselective preparation of these compounds presents many synthetic challenges. This article introduces streamlined access to a versatile chiral biaryl template through C-H halogenation reactions employing high-valent Pd catalysis combination with transient directing groups. methodology is highly scalable, insensitive moisture air, proceeds, select...
ConspectusThe concept of umpolung, or polarity reversal, introduced by Seebach and Corey nearly half a century ago, ushered new paradigm into synthetic chemistry. Novel connections were able to be forged among functional groups that typically inaccessible. Conceptually, an umpolung reaction is identified only upon retrosynthetic analysis. Stoichiometric examples have served as platform develop refine elegant methodologies catalytic processes. The advent these unconventional arrangements...
The SN2 reaction exhibits the classic Walden inversion, indicative of stereospecific backside attack nucleophile on stereogenic center. Observation inversion stereocenter provides evidence for an SN2-type displacement. However, this maxim is contingent substitution proceeding a discrete stereocenter. Here we report that leads to enantioenrichment product despite starting from racemic mixture material. enantioconvergent proceeds through dynamic cycle, involving equilibrating enantiomers,...
Saturated carbonyl compounds are, via their enolate analogues, inherently nucleophilic at the α-position. In presence of a benzoquinone oxidant, polarity α-position racemic α-branched aldehydes is inverted, allowing for an enantioselective etherification using readily available oxygen-based nucleophiles and amino acid-derived primary amine catalyst. A survey oxidants identified p-fluoranil DDQ as suitable reaction partners. p-Fluoranil enables preparation α-aryloxylated phenol in up to 91 %...
Abstract Nucleophile–nucleophile coupling is a challenging transformation in organic chemistry. Herein we present novel umpolung strategy for α‐functionalization of aldehydes with nucleophiles. The uses organocatalytic enamine activation and quinone‐promoted oxidation to access O ‐bound quinol‐intermediates that undergo nucleophilic substitution reactions. These react different classes focus on an unprecedented oxidative α‐thiolation aldehydes. reaction scope demonstrated broad range thiols...
Tropane alkaloids constitute a compound-class which is structurally defined by central 8-azabicyclo[3.2.1]octane core. A diverse bioactivity profile combined with an unusual aza-bridged bicyclic framework has made tropanes molecules-of-interest within organic chemistry. Enantioselective examples of (5+2) cycloadditions between 3-oxidopyridinium betaines and olefins remain unexplored, despite being useful reagents in synthesis. The first asymmetric cycloaddition reported, affording tropane...
Results of an examination the organocatalytic enantioselective α-chlorination 2-phenylpropanal are described. Synthetic investigation including screening primary and secondary aminocatalysts, many different reaction conditions, other α-branched aldehydes show that especially aminocatalysts can catalyze formation α-chloro branched in good yields, but only with moderate enantioselectivities. In order to try understand challenge obtaining high enantioselectivity for aminocatalytic a series...
Abstract A novel cascade reaction initiated by an enantioselective aminocatalysed 1,3‐dipolar [6+4] cycloaddition between catalytically generated trienamines and 3‐oxidopyridinium betaines is presented. The cycloadduct spontaneously undergoes intramolecular enamine‐mediated aldol, hydrolysis, E1cb sequence, which ultimately affords a chiral hexahydroazulene framework. In this process, three new C−C bonds stereocenters are formed, enabled formal unfolding of the pyridine moiety from dipolar...
Abstract Saturated carbonyl compounds are, via their enolate analogues, inherently nucleophilic at the α‐position. In presence of a benzoquinone oxidant, polarity α‐position racemic α‐branched aldehydes is inverted, allowing for an enantioselective etherification using readily available oxygen‐based nucleophiles and amino acid‐derived primary amine catalyst. A survey oxidants identified p ‐fluoranil DDQ as suitable reaction partners. ‐Fluoranil enables preparation α‐aryloxylated phenol in up...