Acceleration of Enantioselective Cycloadditions Catalyzed by Second-Generation Chiral Oxazaborolidinium Triflimidates by Biscoordinating Lewis Acids
作者:Barla Thirupathi、Simon Breitler、Karla Mahender Reddy、E. J. Corey
DOI:10.1021/jacs.6b08018
日期:2016.8.31
oxazaborolidines by the strong acid triflimide (Tf2NH) in CH2Cl2 solution leads to highly active chiralLewis acids that are very effective catalysts for (4 + 2) cycloaddition. We report herein that this catalytic activity can be further enhanced by the use of Tf2NH in combination with the biscoordinating Lewis acid TiCl4 or SnCl4 as a coactivator. The effective increase in acidity of an exceedingly strong
Light-mediated cyanomethylation of cycloalkenes with acetonitrile
作者:Harikisan R. Sonawane、Nanjundiah S. Bellur、Virendra G. Shah
DOI:10.1039/c39900001603
日期:——
Addition of cyanomethyl radicals generated from acetonitrile involving initiation by photoinduced decomposition of hydrogen peroxide, to cycloalkenes has been achieved; a method for the synthesis of two homologous nitriles is first reported.
Stereoselective synthesis of constrained norbornane-derived spiro-β-lactams
作者:Giuseppe Cremonesi、Piero Dalla Croce、Alessandra Forni、Concetta La Rosa
DOI:10.1016/j.tet.2012.11.048
日期:2013.1
New enantiopure polycyclic norbornane-derived spiro-β-lactams were synthesized by means of a Staudinger ketene–imine reaction between unsymmetricalbicyclic chiral ketenes, generated from differently substituted norbornane carboxylic acids, and (E)-N-benzyl-N-(phenylmethylene)amine, with high yields and moderate to good stereoselectivities. The diastereoisomeric results were rationalized taking into
suggest that the nature of the observed phenomena is not a classical equilibration of intermediates found in dynamickineticresolution process but is a result of a different reactivity of both enantiomers of racemic substrate towards the same chiral nucleophile. Reaction of racemic phosphinic acid derivatives with chiral alcohols proceeds with predominant formation of one diastereomer. The highest level
[EN] TERPENE AND TERPENOID DERIVATIVES CONTAINING VINYL GROUPS FOR THE PREPARATION OF POLYMERS<br/>[FR] DÉRIVÉS DE TERPÈNE ET TERPÉNOÏDES CONTENANT DES GROUPES VINYLE POUR LA PRÉPARATION DE POLYMÈRES
申请人:UNIV NOTTINGHAM
公开号:WO2015162419A1
公开(公告)日:2015-10-29
The invention relates to a method for producing functionalised monomers, the method comprising: a) providing a starting material selected from terpenes and terpenoids; b) forming a derivative of the starting material by incorporation of a hydroxyl group; c) esterifying the hydroxyl group of the derivative to introduce a moiety containing a vinyl group, so as to produce a functionalised monomer. The functionalised monomer can be polymerised to obtain a bio-derived polymer.