A new asymmetric approach toward 5-substituted pyrrolidin-2-one derivatives

✍ Scribed by Giovanni Poli; Simone Ciofi Baffoni; Giuliano Giambastiani; Gianna Reginato

• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 916 KB
• Volume: 54
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)00494-3

✦ Synopsis

The condensation between a chiral 2-silyloxypyrrole and either achiral or chiral formyl cation equivalents has been studied. The inethodolo~ has allowed Co build-up 5-substituted pyrrolidin-2-onc derivatives with a stereocontrol from good to excellent. The ehiral auxiliaD, located on the silylox.ypyrrole showed an intrinsic good level of diastereoface discrimination at C-5. However, the use of a 2-methoxw-3-tosyl-oxazolidine as chiral formylating agent allowed a total stereocontrol in the condensation. A rationale for the observed stereochemical outcome is presented. The stereoselective manipulation of these adducts provided new potentially interesting pyroglutamic aldehyde and prolinal derivatives, whereas treatment with TiCI4 triggered unexpectedly a Pomeranz-Fritsch type intramolecular condensation affording a benzocondensated indolizidinone.