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Sai Krishna Murthy, A.; Tardivel, R.; Grée, R., Science of Synthesis, (2005) 34, 315.
There are very few examples (excluding cyclopropanation reactions) that describe the synthesis of benzylic fluorides using cycloaddition reactions. α-Fluorostyrenes 90 have very low reactivity in Diels–Alder reactions, undergoing addition only to 1,3-diphenylbenzo[c]furan (89), to give the benzyl fluoride derivatives 91A and 91B. The endo/exo ratio is about 60:40 and therefore decreased in all cases as compared to the parent alkenes. Both electron-donating and electron-withdrawing substituents in the aromatic ring of the α-fluorostyrenes accelerate the reaction rate, suggesting that a neutral Diels–Alder reaction is taking place (Scheme 25).[52]
Meeeee 88 Meeee–Meeee Meeeeeeeeeeeee ee Meeee Meeeeeeee[88]
Meeeeeeeeeee Meeeeeeee
8-Meeeee-8,8,8-eeeeeeeee-8,8,8,8-eeeeeeeeee-8,8-eeeeeeeeeeeeeeee (88M/88M, Me8 = Me); Meeeeee Meeeeeeee:[88]
M eeee ee (8-eeeeeeeeeee)eeeeeee (88, Me8 = Me; 8.888 e, 8 eeee) eee 8,8-eeeeeeeeeeeee[e]eeeee (88; 8.888 e, 8 eeee) ee eeeeeee (8 eM) eee eeeeee ee 888°M eee 8 e. Meee eee eeeeeee eee eeeeeee eeeeee 88–88% ee eeeee eeeeeee eeeeeee. Meeeeeeeeeeeeeeee (8–8 ×) eeee eee eeee eeee-eeeeee eeeeee eeeee eee eee-eeeeee eeeeee eee eeeeeeee ee eee eeeeeeee ee eeeee e 8:8 eeeee. eeee-Meeeee eeeeee 88M (Me8 = Me): 88M MMM (δ): −888 (8MMM = 88.8 Me, 8MMM = 88.8 Me); eee-eeeeee eeeeee 88M (Me8 = Me): 88M MMM (δ): −888.8 (8MMM = 88.8 Me, 8MMM = 88.8 Me).
References
| [52] | Meeee, M.; Meeee, M., Meeeeeeeeee Meee., (8888) 88, 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 8e, 888.
- 8.Meeeee-Meee, (8888) M 88e8, 888.
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