Robinson annulation
From Freepedia
The Robinson annulation is a chemical reaction used to create a six-membered ring α,β-unsaturated ketone using a ketone (or aldehyde) and methyl vinyl ketone.
- Rapson, W. S.; Robinson, R.; J. Chem. Soc. 1935, 1285.
- Bergmann, E. D.; Gingberg, D.; Pappo, R. Org. React. 1959, 10, 179.
- Gawley, R. E. Synthesis 1976, 777-794.
- Heathcock, C. H.; Ellis, J. E.; McMurry, J. E.; Coppolino, A. Tetrahedron Lett. 1971, 12, 4995.
- Heathcock, C. H.; Mahaim, C.; Schlecht, M. F.; Utawanit, T. J. Org. Chem. 1984, 49, 3264.
- Organic Syntheses, Coll. Vol. 7, p.368; Vol. 63, p.37 (Article)
- Organic Syntheses, Coll. Vol. 6, p.781; Vol. 53, p.70 (Article)
- Organic Syntheses, Coll. Vol. 5, p.869; Vol. 45, p.80 (Article)
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Reaction Mechanism
Methyl vinyl ketone (or variants thereof) are essential for the Robinson annulation as they are simultaneously a Michael acceptor and able to take part in an aldol condensation. The first step in the Robinson annulation is a Michael addition followed by aldol condensation to make the desired cyclohexenone ring.
Variations
Wichterle reaction
The Wichterle reaction is a variant of the Robinson annulation that replaces methyl vinyl ketone with 1,3-dichloro-cis-2-butene
- Wichterle, O. et al. Coll. Czech. Chem. Commun. 1948, 13, 300.
- Kobayashi, M.; Matsumoto, T. Chem. Lett. 1973, 957.
