Stereospecific Synthesis of 2-Oxazinyl-4-oxoazetidinecarbamates Starting from a 1,2-Diazepine. A new type of intramolecular transbenzoylation

✍ Scribed by Hans Fritz; Jean-Michel Henlin; Théophile Tschamber; Jacques Streith; Andreas Riesen; Margareta Zehnder

• Book ID: 102860086
• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: German
• Weight: 794 KB
• Volume: 71
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19880710418

✦ Synopsis

Dedicated to Professor Edward C. Taylor at the occasion of his 65th anniversary (5. IV. 88) Azetidinodiazepines 4b and 4c react with acylnitroso dienophiles 5a+, specifically from their convexe a -side, but in a non-regiospecific way, leading thereby stereospecifically to the expected adducts 6 a 4 and 7a-d. The three-dimensional structures of 6a and 7a were determined by X-ray analyses which corroborated their NMR data. Os04 cis-glycolization occurred in good yield with the inverse adducts 7a and 7e and led to the rearranged products 10. These latter ones result from an intramolecular N-to 0-transbenzoylation of the short-lived intermediates 9 followed by fragmentation of the aminal function. X-Ray analysis of 7a showed the N(10) atom to be pyramidal, a result which demonstrates that it does not have any pronounced benzamide character; otherwise no such N-to 0-transbenzoylation would have taken place. Structure and relative configuration of 10a were ascertained by X-ray analysis which confirmed its NMR data as well as the stereochemical outcome of its formation.