20.500.12556/RUL-134970 Mechanistic insights into annulation of arylidene- [Delta] [sup] 2-pyrrolin-4-ones by cinchona squaramide-based organocatalysts Arylidene-Δ2-pyrrolin-4-ones undergo organocatalyzed annulation with malononitrile, furnishing dihydropyrano[3,2-b]pyrroles (18 examples, 0–77% ee in dichloromethane, 11–44% ee in methanol). The products could be enantiomerically enriched by trituration (11 examples, 95–99% ee). Enantioselectivity was dependent on the nature of the substrate and the conformation of the catalyst, which in turn was solvent-controlled. The reaction mechanism, which included two pseudo-enantiomeric organocatalyst conformations, was investigated by experimental and quantum chemical methods. The reaction mechanism consists of Michael addition reaction step followed by 6-exo-dig annulation, which was found to be the rate determining step. Additionally, it was identified that the preferred reaction pathway follows the model originally proposed by Pápai et al. organocatalysis asymmetric synthesis enantioselectivity solvent effects pyrrolone pseudo-enantiomeric catalyst conformations organokataliza asimetrična sinteza enantioselektivnost učinki topil piroloni psevdo-enantiomerne konformacije katalizatorja true false true Angleški jezik Slovenski jezik Članek v reviji 2022-02-15 12:35:54 2022-02-15 12:35:57 2022-09-14 04:10:56 0000-00-00 00:00:00 2022 0 0 Str. 1-14 iss. Vol. 464 2022 0000-00-00 PostprintKoncna VTisku NiDoloceno 0000-00-00 0000-00-00 0000-00-00 2023-01-14 547.74:544.47 1615-4150 10.1002/adsc.202101369 97278211 RAZ_Ciber_Luka_2022.pdf RAZ_Ciber_Luka_2022.pdf 1 D370D3C8E1C023330AF7CA8A385C46D0 6a17712de37d36acba229e57b6a7b1c0d6aafa428f890e5e44b0979ea526be5e 0af7cca9-8e54-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=153763 https://onlinelibrary.wiley.com/doi/10.1002/adsc.202101369 1 35a3faf9-8e53-11ec-abdb-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=153762 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0