Asymmetric azidohydroxylation of styrene derivatives mediated by a biomimetic styrene monooxygenase enzymatic cascade
作者:Lía Martínez-Montero、Dirk Tischler、Philipp Süss、Anett Schallmey、Maurice C. R. Franssen、Frank Hollmann、Caroline E. Paul
DOI:10.1039/d1cy00855b
日期:——
established a cascade for the asymmetric azidohydroxylation of styrene derivatives leading to chiral substituted 1,2-azido alcohols via enzymatic asymmetric epoxidation, followed by regioselective azidolysis, affording the azido alcohols with up to two contiguous stereogenic centers. A newly isolated two-component flavoprotein styrene monooxygenase StyA proved to be highly selective for epoxidation
Clean and green: Copper(I) complexes of phenanthroline‐based ligands anchored on the chitosan polymer are good catalysts for the “click” cycloaddition of azides with terminal alkynes (see scheme; the scanning electron microscopy image shows the porous structure of the catalyst). These heterogeneous catalytic systems do not require a base or reducing agent and operate in alcohol or water.
[reaction: see text] The reaction outcome of 2-azidoethanol and aliphatic aldehyde is found to be dependent on the catalyst and the structure of the azido alcohol. Under the catalysis of Cu(II) triflate, the corresponding acetal is obtained. A similar reaction between 2-aryl-2-azidoethanol and aldehyde catalyzed by BF3 yields a mixture of 3-oxazoline and 2-oxazoline. The latter reaction has been used
Intramolecular azide-alkyne [3 + 2] cycloaddition: versatile route to new heterocyclic structural scaffolds
作者:Rongti Li、Daniel J. Jansen、Apurba Datta
DOI:10.1039/b818962e
日期:——
relatively unexplored intramolecular version of the azide-alkyne [3 + 2] cycloaddition, the present studies demonstrate the utility of the above reaction in the synthesis of a variety of as yet unreported heterocyclic structural scaffolds. The approach involved initial installation of strategic azide and alkyne moieties on a common structural framework, followed by their intramolecular cycloaddition studies
Nucleophilic Addition to Iminium Ethers in the Preparation of Functionalized <i>N</i>-Alkyl Heterocycles
作者:Erik Fenster、Brenton T. Smith、Vijaya Gracias、Gregory L. Milligan、Jeffrey Aubé
DOI:10.1021/jo702193g
日期:2008.1.1
synthesized by the reactions of ketones with hydroxyalkyl azides. These cationic species react with a variety of nucleophiles via two possible pathways. The initially formed, kinetic product arises from direct addition to the iminium carbon in the substrate. In some cases, the initial adduct reverts to the starting iminium ether and the ultimate product arises from nucleophilic displacement at the