N1–C4 β-Lactam Bond Cleavage in the 2-(Trimethylsilyl)thiazole Addition to β-Lactam Aldehydes: Asymmetric Synthesis of Spiranic and Tertiary α-Alkoxy-γ-keto Acid Derivatives

✍ Scribed by Benito Alcaide; Pedro Almendros; María C. Redondo

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 109 KB
• Volume: 2007
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200700231

✦ Synopsis

Abstract

Starting substrates, enantiopure spiranic or 3‐substituted 3‐alkoxy‐4‐oxoazetidine‐2‐carbaldehydes, were prepared from (R)‐2,3‐O‐isopropylideneglyceraldehyde derived azetidine‐2,3‐diones by sequential Barbier‐type addition reactions followed by hydroxy functionalization and aldehyde unmasking. The reaction between the above β‐lactam aldehydes and 2‐(trimethylsilyl)thiazole (TMST) gave as major products conformationally constrained α‐alkoxy‐γ‐keto amides, which can be considered both as aldols as well as Passerini‐type products, by N1–C4 β‐lactam bond cleavage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)