A novel biomimetic route to the 3-acyl-5-hydroxy-3-pyrrolin-2-one and 3-acyl-3,4-epoxy-5-hydroxypyrrolidin-2-one ring systems

Modified Moffat oxidation of alcohols 17, 22, and 25 afforded aldehydes that underwent intramolecular aldol reactions on treatment with a NaOH solution to yield 4-pyrrolin-2-ones 16, 23, and 26. Oxidation with DMDO at -40 degreesC provided 3-acyl-5-hydroxy-3-pyrrolin-2-ones 18, 24, and 27 with the ring system of oteromycin (3), UCS1025A (5), and related natural products. Further oxidation of 18 yielded 3-acyl-3,4-epoxy-5-hydroxy-pyrrolidin-2-one 19 with the ring system of fusarin C (1) and epolactaene (2). Dehydration of 18 afforded 20 with the talaroconvolutin A (4) ring system.