You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via8.2.11.1.2 Variation 2: Dimetalation of Dialkylarenes
Please login to access the full content or check if you have access via
Mordini, A.; Valacchi, M., Science of Synthesis, (2006) 8, 1228.
The o-, m-, and p-xylenes undergo mono- and even dimetalation by treatment with pentylsodium, although the yields of the corresponding dicarboxylic acids obtained following carbonation are quite low (19, 37, and 36%, respectively, for ortho-, meta-, and para-isomers).[8] If the pentylsodium–N,N,N′,N′-tetramethylethylenediamine reagent is used, o- and m-xylenes are both very efficiently converted into their dimetalated derivatives in quantitative yields; p-xylene furnishes only the monometalated product.[15,16] With the same reagent, an efficient double metalation of dimethylnaphthalenes has also been reported.[15,16] For example, dimetalation of 1,3-dimethylnaphthalene, followed by reaction with iodomethane, gives 1,3-diethylnaphthalene (2) in quantitative yield (Scheme 2).
Meeeee 8 Meeeeeeeee ee 8,8-Meeeeeeeeeeeeeeeeee eee Meeeeeee eeee Meeeeeeeeee[88]
Meeeeeeeeeee Meeeeeeee
8,8-Meeeeeeeeeeeeeeeee (8):[88]
MMMMMMM: Meeeeeeeee, eeeeeeeee, ee eeee eeeeeeeeee ee eeeeeeeeeee eee ee eeeee.
Me e eeeeeee (8888–88888 eee) eeeeeeeeee ee eeeeeeeeeeee [eeeeeeee eeee 8-eeeeeeeeeeeee (8.88 e, 8.88 eee) eee Me (8.88 e, 8.88 eee) ee eeeee eeeeee (88 eM)] ee −88°M, eee eeeee e eeee ee 8,8-eeeeeeeeeeeeeeeeeee (8.88 e, 8.88 eee) eee MMMMM (8.88 e, 8.88 eee) ee eee eeeeee (88 eM), eeee e eeeeee ee 8 eee. Mee eeee eeee eee eeee eeeeeee eee eee eeeeeee eee eeeeeee ee eeee eeeeee ee ee. Meeeeeeeeeee eee eeeeeeeee ee eeeeeeee eee ee eeeeeeeeee 8 e ee ee. Mee eeeeeee eee eeee eeeeee ee 8–8°M eee MeM (8.88 e, 8.88 eee) eee eeeee eeee e eeeeee ee 8–88 eee. Mee eeee eeee eee eeeeeee eee eee eeeeeee eee eeeeeee eee 88 eee ee ee. M8M (88 eM) eee eeee eeeee, eee eeeeee eeee eeeeeeeee, eee eee eeeeeee eeeee eee eeeeee eeee 8 M ee MMe (8 × 88 eM), eee. ee MeMMM8 (8 × 88 eM), eee M8M (88 eM); ee eee eeee eeeee (MeMM8) eee eee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee; eeeee: >88%.
References
[8] | Meeeee, M. M.; Meeeee, M. M.; Meeeee, M. M., M. Me. Meee. Mee., (8888) 88, 8888. |
[15] | Meeeeeeee, M. M.; Meeeee, M.; Meeee, M. M.; Meeeeeeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[16] | Meeeeeeee, M. M.; Meeeee, M.; Meeee, M. M., M. Me. Meee. Mee., (8888) 88, 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 88e, 888.