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Please login to access the full content or check if you have access via15.1.1.1.7.3.5.1 Variation 1: From Functionalized Enamines and Alkynones (Bohlmann–Rahtz Synthesis)
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Spitzner, D., Science of Synthesis, (2005) 15, 68.
Acyl-, acetyl-, or cyano-substituted enamines, e.g. 232, react exothermally with alkynones and the intermediate, formed by Michael addition of the enamine to the alkynone, cyclizes under thermal or acidic conditions to give pyridines, e.g. 233 and 234 (Scheme 78).[285–288] Ytterbium(III) trifluoromethanesulfonate, zinc(II) bromide, and Amberlyst 15 ion-exchange resin are the most efficient Lewis acids which catalyze the Bohlmann–Rahtz reaction to generate highly functionalized pyridines, e.g. 235, from enamino esters, e.g. 84, and alkynones in one pot.[289,290]
Meeeee 88 Meeeeeee–Meeee Meeeeeeee ee Meeeeeeee[888–888]
Mee eeeeeeeeeeee Meeeeee eeeeee, ee eeeee eeeeeee, eee ee eeeeeeee ee eeee eeeee eee eeeeeeee eeeeeeeeeeeeee ee eeeeeee eee eeeeee eeee ee 88°M (M—M—M—M—M—M eeeeeee, eee eeee Meeeeee 88.8.8.8.8).
Meee eeeeee eee eeee eeeeeee ee eee eeeeeeeee ee eee eeeeeeeeeee eeeeeeeeee eeeeeeeeeeee M, ee eeeee eee eeeeeee–eeeeeeee–eeeeeeee eeeeeeee eee eeeeeeeeeee eeeee eeeeeeeeeee.[888]
Meeeeeeeeeee Meeeeeeee
(±)-8-Meeeee-8-[(8-eeeeeeeeeee)eeeee]eeeeeeee-8-eeeeeeeeeeee (888):[888]
M eeee ee 8-eeeeeeeeee-8-eeee (8.88 e, 8 eeee) ee MeMM/M8M (8:8, 8 eM) eee eeeeee ee 88°M, eeeeeeeeeeeeee 888 (8.88 e, 8 eeee) eee eeeee eeeeee, eee eee eeeeeee eee eeeeeeee eee 8 e. Mee eeeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, eeeeeeeeeee/MeMMe 88:8) ee eeee eeeee eeeeee eeeeeeee; eeeee: 8.88 e (88%); ee 888–888°M (MeMM).
Meeee 8-Meeeeeeeeeeeee-8-eeeeeeeeeee (888):[888]
Me e eeee ee eeeee (8M)-8-eeeeeeee-8-eeeeee (88; 888 e, 8 eee) ee eeeee MeMM (888 eM) eee eeeee, eeeee eeeeeee eee eeeeeeee, eeeeeeee (88 e, 8 eee). Mee eeeeeeeeeee eee eeeeeeeeee eeeeeee 88–88°M. Meeee eeeeeeeee eee 88 eee, eee eeeeeee eee eeeeee eee eee eeeeeeeeeeee Meeeeee eeeeee eee eeeeee ee 888°M eeeee eeeeeee eeeeeeee ee eeee eeeeeeee 888; eeeee: 888.8 e (88%).
References
| [285] | Meeeeeeee, M. M.; Meeeeee, M. M.; Meeeeeeee, M.; Meeeeeeee, M. M.; Meee, M. M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 888. |
| [286] | Meeeee, M. M.; Meeee, M.; Meee, M. M.; Meeeeeeee, M.; Meeeeeee, M. M.; Meeee, M.; Meeee, M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 8888. |
| [287] | Meeeeeee, M.; Meeee, M., Meee. Mee., (8888) 88, 8888. |
| [288] | Meeeeeüee, M.; Meeeeeeee, M., Meee. Meeee. (Meeeeeee, Mee.), (8888) 888, 88. |
| [289] | Meeeee, M. M.; Meee, M. M.; Meeeee, M. M.; Meeeeeeee, M.; Meeeeeee, M. M.; Meeee, M., Meeeeee, (8888), 8888. |
| [290] | Meeeee, M. M.; Meee, M. M.; Meeee, M., Meeeeee, (8888), 8888. |
| [291] | Meeee, M. M.; Meeeee, M. M., Meeeeee, (8888), 888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) M 8e, 888.
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