ol6b00287_si_002.cif (1.01 MB)

Enantioselective Synthesis of Dihydrospiro[indoline-3,4′-pyrano[2,3‑c]pyrazole] Derivatives via Michael/Hemiketalization Reaction

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posted on 04.03.2016, 15:03 by Nandarapu Kumarswamyreddy, Venkitasamy Kesavan
A new bifunctional squaramide organocatalyst derived from l-proline mediated the first enantioselective synthesis of dihydrospiro­[indoline-3,4′-pyrano­[2,3-c]­pyrazole] derivatives in excellent enantioselectivity by reacting pyrazolones with isatylidine β,γ-unsaturated α-ketoester. This new catalyst outperformed widely used thioureas and squaramides in inducing enantioselectivity.