Ni(<scp>ii</scp>)-Catalyzed vinylic C–H functionalization of 2-acetamido-3-arylacrylates to access isotetronic acids
作者:Biswajit Roy、Eshani Das、Avijit Roy、Dipakranjan Mal
DOI:10.1039/d0ob00557f
日期:——
reaction for the synthesis of 4-aryl-substituted isotetronic acids from 2-acetamido-3-arylacrylates via vinylic C-H functionalization is reported. The reaction proceeds through heteroatom guided electrophilic insertion of nickel to the vinylic double bond followed by annulation with dibromomethane. This unconventional route features cascade steps, sole product formation, multiple functional group tolerance
Base catalysed rearrangements involving ylide intermediates. Part 11. Rearrangements of 3-phenylprop-2-ynylammonium ylides
作者:Sivapathasuntharam Mageswaran、W. David Ollis、Dolores A. Southam、Ian O. Sutherland、Yodhathai Thebtaranonth
DOI:10.1039/p19810001969
日期:——
novel [1,3] rearrangementinvolving the migration of a dimethylamino-group. The basecatalysedrearrangements of the bicyclic propynylammonium salts (52) and (56) do not show the inhibition expected for concerted [3,2] sigmatropic rearrangements in such bicyclic systems. This observation provides further evidence for a two-stage mechanism for the apparent [3,2] sigmatropic rearrangement of propynylammonium
1,5-Hydride shift in products of Stevens 3,2-rearrangement of methyl(alkyl)(alkoxycarbonylmethyl)-(3-phenyl-2- propynyl)ammonium bromides
作者:V. S. Ovsepyan、A. V. Babakhanyan、M. O. Manukyan、S. T. Kocharyan
DOI:10.1007/s11176-005-0014-7
日期:2004.9
The products of the Stevens 3,2-rearrangement of ammonium salts containing methyl and other (ethyl, propyl, butyl) alkyl groups along with 3-phenylprop-2-ynyl, under the reaction conditions undergo, roughly by half, intramolecular hydride shift with intermediate formation of immonium salts. The latter convert into enamino esters whose hydrolysis involving alkyl groups at the nitrogen atom gives rise to lower aliphatic aldehydes and the corresponding amino esters. Treatment with dilute hydrochloric acid of the reaction mixture containing enamino esters results in formation of hydrogenated and nonhydrogenated alkyl esters of α-keto acids. This mixture was reacted with concentrated hydrochloric acid to obtain 3-hydroxy-5-methyl-4-phenylfuran-2(5H)-one from the nonhydrogenated keto ester and to isolate pure the hydrogenated keto ester.
A novel doublecarbonylation of styreneoxides occurs on treatment of the heterocycle with carbon monoxide, methyl iodide, NaOH (0.5 M), C6H6, Co2(CO)8 as the metal catalyst and cetyltrimethylammonium bromide as the phasetransfer agent.
在用一氧化碳,碘甲烷,NaOH(0.5 M),C 6 H 6,Co 2(CO)8作为金属催化剂和十六烷基三甲基溴化铵作为相转移剂处理杂环时,发生苯乙烯氧化物的新型双羰基化反应。
Intramolecular 1,5-Hydride Shift in Products of Stevens 3,2-Rearrangement of Ammonium Salts Containing 3-Phenyl-2-propynyl Group
作者:A. V. Babakhanyan、V. S. Ovsepyan、S. T. Kocharyan、G. A. Panosyan
DOI:10.1023/b:rujo.0000003157.80528.0a
日期:2003.6
In products of Stevens 3,2-rearrangement of ammonium salts containing alongside alkoxycarbony-ymethyl also 3-phenyl-2-propynyl group an intramolecular 1,5-hydride shift is observed resulting in immonium salts which transform into antinoesters of enamine structure. The hydrolysis of the latter provides the lower aliphatic aldehydes and the corresponding aminoesters. An acid treatment of the reaction mixture affords a mixture of hydrogenated and nonhydrogenated esters of alpha-ketoacids originating from the mixture of 1,3-diene antinoesters. At treating, with concn. HCl of the obtained mixture the nonhydrogeneted ketoester undergoes cyclization into 4-methyl-3-phenyl-2-buten-1,4-olide.