✦ LIBER ✦
Stereoelectronic control in ring opening of bridge-head nitrogen containing fused azolium salts
✍ Scribed by András Messner; György Hajós; Géza Tímári
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- French
- Weight
- 569 KB
- Volume
- 48
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
A&tnw Reaction of tetrazolopyridinium salts 1 with nucleophiles proceeds through the neutral intermediate 2. Ring opening of this leads to hetatylbutadienes (3,4,5) of different geometries. Experimental support has been provided for the theoretical supposition that 2 before opening up can undergo nitrogen inversion and the hvo invertomers of this intermediate (2A and 2B) react via the two possible senses of disrotation, one of them (2A) under stereoekxtronic control. By this mechanism unexpected stereosektivities are explained and the degree of selectivity can be predicted.