Photochemie von Aminoketonen, 14. Synthese und transannulare Photocyclisierung von 2-Benzoyl-1,4-bis(tosyl)piperazinen
✍ Scribed by Wessig, Pablo ;Legart, Frank ;Hoffmann, Berit ;Henning, Hans-Georg
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 383 KB
- Volume
- 1991
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Photochemistry of Amino Ketones, 14^1)^. – Synthesis and Transannular Photocyclisation of 2‐Benzoyl‐1,4‐bis‐(tosyl)piperazines
1,1‐Dialkyl‐1,2‐bis(tosylamino)ethanes 4 are prepared in a three‐step reaction starting with dialkyl ketones 1. With strong bases in dimethylformamide compounds 4 react regioselectively with 1,2‐dibromoalkyl phenyl ketones 5 to afford the 2‐benzoyl‐1,4‐bis(tosyl)piperazines 6. On irradiation (≥ 300 nm) the piperazines 6a, b, f, g, without substituents in position 6, undergo Norrish‐II cleavage yielding open‐chain products. Depending on the ring conformations the 2,2‐dialkylpiperazines 6c, d, e form diazabicycloalkanes 10 and 11 on irradiation.