Mechanistic Insights into Annulation of Arylidene‐Δ <sup>2</sup> ‐Pyrrolin‐4‐Ones by Cinchona Squaramide‐Based Organocatalysts
نویسندگان
چکیده
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% methanol). The products could be enantiomerically enriched by trituration (11 95–99% ee). Enantioselectivity was dependent on the nature of substrate and conformation catalyst, which turn solvent-controlled. reaction mechanism, included two pseudo-enantiomeric organocatalyst conformations, investigated experimental quantum chemical methods. mechanism consists Michael addition step followed 6-exo-dig annulation, found to rate determining step. Additionally, it identified that preferred pathway follows model originally proposed Pápai et al.
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ژورنال
عنوان ژورنال: Advanced Synthesis & Catalysis
سال: 2022
ISSN: ['1615-4169', '1615-4150']
DOI: https://doi.org/10.1002/adsc.202101369