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Double Spirocyclization of Arylidene-Δ<sup>2</sup>-Pyrrolin-4-Ones with 3-Isothiocyanato Oxindoles
oleh: Sebastijan Ričko, Žan Testen, Luka Ciber, Franc Požgan, Bogdan Štefane, Helena Brodnik, Jurij Svete, Uroš Grošelj
Format: | Article |
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Diterbitkan: | MDPI AG 2020-10-01 |
Deskripsi
Arylidene-Δ<sup>2</sup>-pyrrolin-4-ones undergo organocatalyzed double spirocyclization with 3-isothiocianato oxindoles in a domino 1,4/1,2-addition sequence. The products contain three contiguous stereocenters (<i>ee</i> up to 98%, <i>dr</i> up to 99:1, 12 examples). The absolute configuration of the major diastereomer was determined by single crystal X-ray analysis. Along with heterocyclic Michael acceptors based on oxazolone, isoxazolone, thiazolidinone, pyrazolone, and pyrimidinedione, the reported results display the applicability of unsaturated Δ<sup>2</sup>-pyrrolin-4-ones (pyrrolones) for the organocatalyzed construction of 3D-rich pyrrolone-containing heterocycles.