A Self-Assembled Molecular Cage for Substrate-Selective Epoxidation Reactions in Aqueous Media
作者:Petrus F. Kuijpers、Matthias Otte、Maximilian Dürr、Ivana Ivanović-Burmazović、Joost N. H. Reek、Bas de Bruin
DOI:10.1021/acscatal.6b00283
日期:2016.5.6
allows catalytic epoxidation of various substrates in 1:1 water/acetonitrile mixtures. The cage acts as a phase-transfer catalyst and creates a protective environment for the catalyst improving the stability. The encapsulated catalyst also allows discrimination between styrenederivatives of various sizes. In a direct competition experiment, the selectivity of the epoxidationreaction could be inverted
Activation of Carboxylic Acids in Asymmetric Organocatalysis
作者:Mattia Riccardo Monaco、Belén Poladura、Miriam Diaz de Los Bernardos、Markus Leutzsch、Richard Goddard、Benjamin List
DOI:10.1002/anie.201400169
日期:2014.7.1
association of carboxylicacids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self‐assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylicacid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine‐opening reaction with carboxylicacids as nucleophiles
Asymmetric Trasformation of Symmetrical Epoxides to Allylic Alcohols by Lithium (<i>S</i>)-2-(<i>N</i>,<i>N</i>-Disubstituted aminomethyl)pyrrolidide
作者:Masatoshi Asami
DOI:10.1246/bcsj.63.721
日期:1990.3
Enantioselective deprotonation of symmetrical epoxides was studied by using chiral lithium amide, prepared from (S)-2-(N,N-disubstituted aminomethyl)pyrrolidine and butyllithium. Chiral allylic alcohols were obtained with moderate to high enantiomeric excesses (ee’s) (41–92% ee) from several cyclic and acyclic epoxides employing lithium (S)-2-(1-pyrrolidinylmethyl)pyrrolidide in tetrahydrofuran (THF) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).
A Novel Epoxidation Reaction of Olefins Using a Combination of Chloramine-M, Benzaldehyde, and Benzyltriethylammonium Chloride
作者:Dan Yang、Chi Zhang、Xue-Chao Wang
DOI:10.1021/ja993472q
日期:2000.5.1
products. Good to excellent diastereoselectivities were obtained for epoxidation of two substitutedcyclohexenes. Chloramine-T was found to give a slower reaction than Chloramine-M. cis-N-Sulfonyloxaziridine D is proposed to be the epoxidizing agent in this novel epoxidation reaction on the basis of the mechanistic studies.