Zinc(<scp>II</scp>)-catalysed transformation of epoxides to aziridines
作者:Dorte Kühnau、Ib Thomsen、Karl Anker Jørgensen
DOI:10.1039/p19960001167
日期:——
The Lewis acid-catalysed transformation of epoxides to aziridines with iminophosphoranes as the nitrogen-fragment donor has been investigated. Of the Lewis acids tested, zinc(II) complexes had the best catalytic properties. The method works best for terminal and cyclic epoxides, internal epoxides being less reactive. Of the various iminophosphoranes employed N-(triphenylphosphoranylidene)-aniline and
Generation of aziridinyllithiums from sulfinylaziridines by the ligand exchange reaction of sulfoxides with tert-butyllithium: Their properties and an application to asymmetric synthesis of α-dialkylamino acid ester
sulfinylaziridines by the ligand exchange reaction of sulfoxides with tert-butyllithium. The aziridinyllithiums were found to be stable in THF at below −30 °C and reactive with several electrophiles such as carbonyl compounds. Synthesis of an optically active α-dialkylamino acid ester was realized via the aziridinyllithium starting from optically active chloromethyl p-tolyl sulfoxide.
Generation of Aziridinyllithiums from Sulfinylaziridines with tert-Butyllithium: Properties, Reactivity, and Application to a Synthesis of α,α-Dialkylamino Acid Esters and Amides Including an Optically Active Form
aziridinyllithiums having several alkyl groups were investigated. As an extension of this method, a synthesis of α,α-dialkylamino acid esters, including an opticallyactive form, and amides was realized via the aziridinyllithiums. N-Non substituted α,α-dialkylamino acid esters were synthesized starting from N-(4-methoxyphenyl) aldimine.
Ring splitting of azetidin-2-ones via radical anions
作者:Raúl Pérez-Ruiz、Jose A. Sáez、Luis R. Domingo、M. Consuelo Jiménez、Miguel A. Miranda
DOI:10.1039/c2ob26528a
日期:——
The radicalanions of azetidin-2-ones, generated by UV-irradiation in the presence of triethylamine, undergo ring-splitting via N–C4 or C3–C4 bond breaking, leading to open-chain amides. This reactivity diverges from that found for the neutral excited states, which is characterised by α-cleavage. The preference for β-cleavage is supported by DFT theoretical calculations on the energy barriers associated
Novel aziridination of α-halo ketones: an efficient nucleophile-induced cyclization of phosphoramidates to functionalized aziridines
作者:Lal Dhar S. Yadav、Ankita Rai、Vijai K. Rai、Chhama Awasthi
DOI:10.1016/j.tetlet.2007.11.130
日期:2008.1
A novel and efficient aziridination of α-haloketones is reported. The reaction of α-haloketones with diethyl N-arylphosphoramidates affords diethyl N-aryl-N-(2-oxoalkyl)phosphoramidates which undergo reductive (H−-induced) cyclization with sodium borohydride followed by sodium hydride to give 1,2-disubstituted and 1,2,3-trisubstituted aziridines. The cyclization induced by NCS− or PhS− affords substituted