90606-10-3Relevant academic research and scientific papers
Enantioselective synthesis of α-heteroarylpyrrolidines by copper-catalyzed 1,3-dipolar cycloaddition of α-silylimines
Pascual-Escudero, Ana,Gonzalez-Esguevillas, Maria,Padilla, Silvia,Adrio, Javier,Carretero, Juan C.
supporting information, p. 2228 - 2231 (2014/05/06)
α-Heteroarylpyrrolidines have been efficiently prepared via 1,3-dipolar cycloaddition between silylimines and activated olefins. In the presence of Cu(CH3CN)4PF6/Walphos as catalytic system, high levels of enantioselectivity (up to >99% ee) and diastereoselectivity were achieved (major formation of C-2/C-4 trans-substituted pyrrolidines). The reaction is compatible with a broad variety of dipolarophiles including maleimides, maleates, fumarates, nitroalkenes, and vinylsulfones. The resulting cycloadducts can be transformed into bioactive pyrrolidine derivatives.
Mechanism and stereoselectivity of the aza-Wittig reaction between phosphazenes and aldehydes
Cossio, Fernando P.,Alonso, Concepcion,Lecea, Begona,Ayerbe, Mirari,Rubiales, Gloria,Palacios, Francisco
, p. 2839 - 2847 (2007/10/03)
The mechanism of the aza-Wittig reaction between phosphazenes and aldehydes has been studied computationally, using DFT methods (B3LYP/6-31G* level), and experimentally. It has been found that the reaction consists of a tandem [2+2] cycloaddition-cycloreversion sequence in which π and σ orbitals as well as lone pairs are involved. Both [2+2] processes take place via thermally allowed supra-supra mechanisms. P-trimethyl-λ5- phosphazenes are predicted to be more reactive than their P-triphenyl analogues. The stereochemical outcome of the whole reaction depends only on the second step, because conformational changes in the intermediate 1,3,2- λ5-oxazaphosphazetidines have a much lower activation energy than the second [2+2] cycloreversion reaction. Preferential or exclusive formation of the corresponding (E)-imines is predicted.
Trifluoromethyl-substituted Δ3-imidazolines: Synthesis and reactivity
Derstine, Christopher W.,Smith, David N.,Katzenellenbogen, John A.
, p. 4359 - 4362 (2007/10/03)
We describe the preparation of various 4-trifluoromethyl-substituted Δ3-imidazolines, which are precursors to amino acid-derived trifluoromethyl ketones. The imidazolines are prepared from α-silylimines and trifluoroacetonitrile by a 3+2 cycloaddition, and they can be hydrolyzed in weak acid to trifluoromethyl ketones. Additionally, we have identified several ring-opened compounds which result from treatment of the imidazolines with acid or base. Attempts to alkylate the imidazolines led to ring-opened products, so that the alkylation sequence ultimately produced N-alkylated amino acid-derived trifluoromethyl ketones.
A SIMPLE EFFICIENT SYNTHESIS OF 3-PYRROLINES USING A 1,3-DIPOLAR CYCLOADDITION REACTION WITH AN YLIDE GENERATED BY THERMAL DESILYLATION OF AN α-SILYLIMINIUM SALT.
Anderson, Wayne K.,Dabrah, Thomas T.
, p. 559 - 564 (2007/10/02)
Treatment of N-(benzylidene)trimethylsilylmethylamine with methyl chloroformate at 50 deg C produced an ylide that reacted with dimethyl acetylenedicarboxylate to give dimethyl 1-methoxycarbonyl-2-phenyl-3-pyrroline-3,4-dicarboxylate.
Synthesis and Antineoplastic Activity of Bisoxy>methyl>-Substituted 3-Pyrrolines as Prodrugs of Tumor Inhibitory Pyrrole Bis(carbamates)
Anderson, Wayne K.,Milowsky, Arnold S.
, p. 2241 - 2249 (2007/10/02)
A series of bispyrrolines 2-4 were synthesized from either the appropriate α-silylated iminium salt, or an aziridine, or a 2H-azirine in a sequence involving 1,3-dipolar cycloaddition reactions.The antineoplastic activities of the pyrrolines were compared to the corresponding pyrroles.The C-2 gem-dimethyl-substituted pyrroline, 4, which cannot be converted to the pyrrole in vivo, was inactive.The activity of the 2-phenyl-substituted pyrrolines 3 was markedly dependent on the nature of the phenyl substituent, although the correspondingphenylpyrroles all showed comparable activity.The differences in the activities of the pyrrolines 3 may be due to the rate of metabolic conversion of the pyrroline to the pyrrole.Electron-withdrawing substituents on the phenyl ring appear to retard this process.
One-Pot Synthesis of N-((Trimethylsilyl)methyl)imines and (Trimethylsilyl)methyl-Substituted Heterocumulenes from (Trimethylsilyl)methyl Azide
Tsuge, Otohiko,Kanemasa, Shuji,Matsuda, Koyo
, p. 2688 - 2691 (2007/10/02)
The reactions of ((trimethylsilyl)methyl)iminotriphenylphosphorane, prepared in situ from (trimethylsilyl)methyl azide and triphenylphosphine, with carbonyl compounds and with heterocumulenes such as carbon dioxide, carbon disulfide, isocyanates, isothiocyanates, and a ketene provide convenient one-pot syntheses of the corresponding N-((trimethylsilyl)methyl)imines and (trimethylsilyl)methyl-substituted heterocumulenes, which are versatile reagents for the synthesis of heterocyclic compounds.
A SILYL-FUNCTIONALIZED ALKYL AZIDE, TRIMETHYLSILYLMETHYL AZIDE; SYNTHESIS AND CYCLOADDITION REACTION TO ACETYLENIC DIPOLAROPHILES
Tsuge, Otohiko,Kanemasa, Shuji,Matsuda, Koyo
, p. 1131 - 1134 (2007/10/02)
Thermally stable trimethylsilylmethyl azide was first synthesized from the reaction of chloromethyltrimethylsilane with sodium azide.Its use as an α-functionalized synthetic equivalent of methyl azide was demonstrated in the reaction with acetylenic dipol
