1,2,3-Triazolidine durch Cycloaddition von Aziminen an Olefine

✍ Scribed by Notker Egger; Roland Prewo; Jost H. Bieri; Lienhard Hoesch; Andre S. Dreiding

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: German
• Weight: 612 KB
• Volume: 66
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19830660530

✦ Synopsis

1,2,3‐Triazolidines by Cycloaddition of Azimines to Olefines

Azimines A can undergo [3+2]‐cycloadditions with olefines B to give 1,2,3‐triazolidines C, a class of hitherto unknown heterocycles. The three examples of this reaction realized here involved the azimine 1 with electron‐withdrawing substituents and the olefines 2, 3 and 4 with an electron‐donating substituent, yielding the cycloadducts 5,6 and 7. The triazolidine structure of 5 was established by an X‐ray diffraction analysis. Characteristic for 5 are also: (a) that the three N‐atoms are pyramidal (and thus centers of chirality), (b) that the five‐membered heterocycle takes on a twist (half‐chair) form, and (c) that the regioselectivity of the cycloaddition places the (E)‐substituent of the olefine 2 vicinal to the terminal (Z)‐substituent of the azimine 1. On this basis the constitutions of 6 and 7 are assigned. The spectral properties of the triazolidines 5, 6 and 7, including the ^15^N‐NMR signals of one example, are compared with those of the related triazane 12.