Results 31 to 40 of about 2,217 (174)

Photochemisch erzeugte Oxetane als Schlüssel zur endergonen Cyclopropansynthese

open access: yesAngewandte Chemie, EarlyView.
Eine neuartige Oxetan‐zu‐Cyclopropan‐Umlagerung eröffnet einen atomökonomischen Zugang zu dicht funktionalisierten Cyclopropanen aus Furanen und photochemisch aktivierten Aldehyden. Die erhaltenen Strukturen erschließen komplexe bioaktive Motive und fungieren als vielseitige Plattform für die asymmetrische Cyclopropansynthese.
Tim Köglmeier   +2 more
wiley   +1 more source

Silylium-Catalyzed Activation of Donor- Acceptor Strained Rings and Annulation with Indoles

open access: yesCHIMIA
Leveraging the unique reactivity profile of donor-acceptor aminocyclopropanes and cyclobutanes allows the preparation of complex nitrogen-substituted molecules. While most reports focus on donor-acceptor strained rings with two geminal carbonyl groups as
Emma G. L. Robert, Jérôme Waser
doaj   +1 more source

Synthesis of Cyclobutane Serine Analogues

open access: yesThe Journal of Organic Chemistry, 2004
In this paper, we describe a thermal [2 + 2] cycloaddition involving 2-acylaminoacrylates as electron-poor acceptor alkenes, a reaction that involves a Michael-Dieckmann-type process. The reaction gives rise to a new substituted cyclobutane skeleton that can be transformed into amino acid derivatives.
Avenoza, A.   +3 more
openaire   +4 more sources

Photogenerated Oxetanes as a Gateway to Uphill Cyclopropanation

open access: yesAngewandte Chemie International Edition, EarlyView.
An atom‐economical route to densely functionalized cyclopropanes from furans and photochemically activated aldehydes is enabled by a unique oxetane‐to‐cyclopropane rearrangement. These cyclopropanes can be used to access complex bioactive scaffolds and serve as a platform for asymmetric cyclopropane synthesis.
Tim Köglmeier   +2 more
wiley   +1 more source

N‐Aryl Acridone Derivatives as Effective Catalysts for Energy Transfer Reactions

open access: yesChemistry – A European Journal, EarlyView.
Acridones derivatives have high triplet energy, are simple accessible, and could be used in challenging [2+2] ENT reactions. ABSTRACT Organic photocatalysts capable of promoting high‐energy triplet energy transfer (EnT) remain limited, particularly for demanding [2+2] photocycloaddition reactions.
Francesco Calogero   +8 more
wiley   +1 more source

Stereochemical Control in the Matteson Reaction

open access: yesChemistry – A European Journal, EarlyView.
The Matteson homologation is a highly versatile method for the stereoselective insertion of carbenoids into boronic esters. Through iterative application of the process, complex chiral molecules can be synthesized. The stereoselectivity of the reaction is determined by a chiral diol incorporated in the boronic ester.
Hae Mo Lee, Christoph Hirschhäuser
wiley   +1 more source

[2+2]-Photocycloadditions of 2-Acetoxy-1,4-naphthoquinone and Structure Determination of the Main Photoadducts

open access: yesPhotochem
The [2+2]-photocycloaddition of 2-acetoxy-1,4-naphthoquinone with 1,1-diphenylethylene, styrene and cyclopentene was conducted in a conventional batch reactor.
Madyan A. Yaseen   +3 more
doaj   +1 more source

Cyclopropylamine‐Derived Distonic Iminium Radicals: Photoinduced Strategies in Chemo‐ and Stereo‐Selective Synthesis

open access: yesChemistry – A European Journal, EarlyView.
Cyclopropylamines have emerged as powerful photocatalytic building blocks. Upon light‐induced single‐electron oxidation, they undergo strain‐release ring opening to generate distonic iminium radicals that enable diverse transformations, including ring‐opening functionalization, formal [3 + 2] cycloadditions, radical cascades, and asymmetric bond ...
Maria Chiara Cabua   +3 more
wiley   +1 more source

Clathrate hydrate crystallization

open access: yesThe Canadian Journal of Chemical Engineering, EarlyView.
Abstract Clathrate hydrate crystallization has been an area of interest to chemical engineers from the point of view of crystal structure, thermophysical properties, phase equilibria, kinetics, industrial applications, and environmental (climate change) implications.
Peter Englezos
wiley   +1 more source

Diastereoselective Synthesis of Highly Substituted Methylene Cyclobutanes by Pd Catalysis

open access: yesEuropean Journal of Organic Chemistry, EarlyView.
A chemo‐ and diastereoselective palladium‐catalyzed intramolecular coupling/cyclization of borylated 1,5‐dienes, readily accessible by allene allylboration, with iodoarenes enables the synthesis of highly substituted methylene cyclobutanes. The method exhibits broad scope, high functional group tolerance, and complete enantiospecificity.
Jose M. Malga   +1 more
wiley   +1 more source

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