Zur Chemie der Mucohalogensäuren, VII. Asymmetrische Synthese von β-Lactam-Derivaten durch Keten — Imin-Cycloaddition unter Verwendung chiraler Mucochlorsäure-Derivate
✍ Scribed by Duczek, Wolfram ;Jähnisch, Klaus ;Kunath, Annamarie ;Reck, Günter ;Winter, Gabriele ;Schulz, Burkhard
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 703 KB
- Volume
- 1992
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Chemistry of Mucohalic Acids, VII. — Asymmetric Synthesis of β‐Lactam Derivatives by the Ketene—Imine Cycloaddition Utilizing Chiral Mucochloric Acid Derivatives
The ketene derivative 5 of the chiral pyrrolinon 4 underwent nonconcerted [2 + 2] cycloadditions with imines leading to cis‐β‐lactams 6a–d with ≫99% diastereomeric excess. rac‐4 was resolved efficiently by crystallisation of diastereoisomeric ammonium salts with brucine. (5__S__)‐4 provided the β‐lactam (3′S,4′R,5__S__)‐6a. The absolute configuration of 6a was determined by X‐ray analysis. The synthesis of the minor β‐lactam 7 was achieved independently.