Nucleophilic Ring Opening of Donor–Acceptor Cyclopropanes Catalyzed by a Brønsted Acid in Hexafluoroisopropanol
作者:Edward Richmond、Vuk D. Vuković、Joseph Moran
DOI:10.1021/acs.orglett.7b03688
日期:2018.2.2
A general, Brønsted acid catalyzed method for the room temperature, nucleophilic ringopening of donor–acceptorcyclopropanes in fluorinated alcohol solvent, HFIP, is described. Salient features of this method include an expanded cyclopropane scope, including those bearing single keto-acceptor groups and those bearing electron-deficient aryl groups. Notably, the catalytic system proved amenable to
Rh(II)-Catalyzed Nitrene-Transfer [5 + 1] Cycloadditions of Aryl-Substituted Vinylcyclopropanes
作者:Logan A. Combee、Shea L. Johnson、Julie E. Laudenschlager、Michael K. Hilinski
DOI:10.1021/acs.orglett.9b00594
日期:2019.4.5
Formal [5 + 1] cycloadditions between aryl-substituted vinylcyclopropanes and nitrenoid precursors are reported. The method, which employs Rh2(esp)2 as a catalyst, leads to the highly regioselective formation of substituted tetrahydropyridines. Preliminary mechanistic studies support a stepwise, polar mechanism enabled by the previously observed Lewis acidity of Rh-nitrenoids. Overall, this work expands
Intermolecular asymmetric cyclopropanation with diazoketones catalyzed by chiral ruthenium porphyrins
作者:Irène Nicolas、Paul Le Maux、Gérard Simonneaux
DOI:10.1016/j.tetlet.2008.01.129
日期:2008.3
The asymmetric addition of diazoacetophenone to styrene derivatives to give optically active cyclopropyl ketones (ee up to 86%) was carried out by using chiral ruthenium porphyrins as homogeneous catalysts.
Asymmetric intermolecular cyclopropanation of alkenes by diazoketones catalyzed by Halterman iron porphyrins
作者:Irène Nicolas、Thierry Roisnel、Paul Le Maux、Gérard Simonneaux
DOI:10.1016/j.tetlet.2009.06.131
日期:2009.9
The asymmetric addition of diazoacetophenone to styrene derivatives to give optically active cyclopropyl ketones (ee up to 80%) was carried out rising chiral iron porphyrins as homogeneous catalysts. Intermolecular N-H functionalization of anilines by means of carbenoid-induced N-H insertion was also possible but without enantioselectivity. (C) 2009 Elsevier Ltd. All rights reserved.