Synthesis of Spiro‐Δ2‐Pyrrolin‐4‐One Pseudo Enantiomers via an Organocatalyzed Sulfa‐Michael/Aldol Domino Sequence


Advanced Synthesis & Catalysis

Uroš Grošelj, Luka Ciber, Jan Gnidovec, Žan Testen, Franc Požgan, Bogdan Štefane, Gašper Tavčar, Jurij Svete, Sebastijan Ričko

Δ2‐Pyrrolin‐4‐ones undergo organocatalyzed sulfa‐Michael/aldol domino spirocyclizations with mercaptoacetaldehyde dimer. The products contain three contiguous stereocenters (ee up to 99%, dr up to 95:5, 25 examples) and can be transformed into analogues of natural products. With the use of a single catalyst, the absolute configuration of the products were determined by the configuration of the exocyclic double bond of the starting material. These results point at the possibility of a widespread use of unsaturated Δ2‐pyrrolin‐4‐ones in various (organo)catalyzed (cascade) transformations for accessing libraries of 3D‐rich pyrrolone‐based (spiro)heterocycles.

Read article: Adv. Synth. Catal., 2019, 361, 5118-5126