6533b834fe1ef96bd129d972
RESEARCH PRODUCT
Exploiting the Chiral Ligands of Bis(imidazolinyl)- and Bis(oxazolinyl)thiophenes : Synthesis and Application in Cu-Catalyzed Friedel–Crafts Asymmetric Alkylation
Mohammad Shahidul IslamAbdullah Saleh AlammariAssem BarakatSaeed AlshahraniMatti HaukkaAbdullah Mohammed Al-majidsubject
bis-imidazolinekemiallinen synteesithiophenekatalyytitFriedel−Crafts alkylationasymmetric catalysisliganditkompleksiyhdisteetbis-oxazolineindolesβ-nitroolefinsdescription
Five new C2-symmetric chiral ligands of 2,5-bis(imidazolinyl)thiophene (L1–L3) and 2,5-bis(oxazolinyl)thiophene (L4 and L5) were synthesized from thiophene-2,5-dicarboxylic acid (1) with enantiopure amino alcohols (4a–c) in excellent optical purity and chemical yield. The utility of these new chiral ligands for Friedel–Crafts asymmetric alkylation was explored. Subsequently, the optimized tridentate ligand L5 and Cu(OTf)2 catalyst (15 mol%) in toluene for 48 h promoted Friedel–Crafts asymmetric alkylation in moderate to good yields (up to 76%) and with good enantioselectivity (up to 81% ee). The bis(oxazolinyl)thiophene ligands were more potent than bis(imidazolinyl)thiophene analogues for the asymmetric induction of the Friedel–Crafts asymmetric alkylation. peerReviewed
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2021-01-01 |