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2,2-bis(trifluoromethyl)ethylene-1,1-dicarbonitrile and styrenes the concertedness of the [2 + 4] cycloaddition

✍ Scribed by Reinhard Brückner; Rolf Huisgen

Publisher
Elsevier Science
Year
1990
Tongue
French
Weight
265 KB
Volume
31
Category
Article
ISSN
0040-4039

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✦ Synopsis

The effects of substituents and solvent variation on the rate constants are in harmony with a concerted cycloaddition. In the preceding communication we described reactions of 2,2-bis(trifluoromethyl)ethylene-1 ,I-dicarbonitrile (BTF; 1) with styrenes 2 2. By rapid reversible Diels-Alder additions we obtained the nonaromatic tetrahydronaphthalenes 5, wheras slower irreversible reactions led to cyclobutanes 4 or ene products 6. The cyclobutanes 4 are most likely formed via the 1,Cdipolar intermediates 3 3f14. This zwitterion 3 could also furnish the ene products 6 by protonationldeprotonation; a concerted pathway, 1 + 2 (R = CH3) + 6, is likewise plausible. NC CF3

📜 SIMILAR VOLUMES

Substitutions and dehydrogenations by 2,
Substitutions and dehydrogenations by 2,2-bis(trifluoromethyl)-ethylene-1,1-dicarbonitrile via hydride abstraction
✍ Reinhard Brückner; Rolf Huisgen 📂 Article 📅 1991 🏛 Elsevier Science 🌐 French ⚖ 291 KB

Substitution of benzylic H by the title compound (BTF) gives rise to products with -CH(CF3)2 terminus exclusively; an intermediate benzylic ion pair results from hydride transfer. Instead of ion recombination, proton transfer may be the concluding step generating dehydrogenation products and 2,2-bis