The Baker–Venkataraman rearrangement is the chemical reaction of 2-acetoxyacetophenones with base to form 1,3-diketones.[1][2]
This rearrangement reaction proceeds via enolate formation followed by acyl transfer. It is named after the 2 scientists W.Baker and Krishnaswamy Venkataraman.
The Baker–Venkataraman rearrangement is often used to synthesize chromones and flavones.[3][4][5][6][7][8][9][10]
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Mechanism
With a base being a catalyst, it attacks hydrogen atom in Acetophenone and an enolate is formed. Then, the enolate group attacks the carbon in the phenol ester to form a cyclic alkoxide. Finally, it opens up a phenolate which is reprocessed by acid to undergo protonation.
References
- ^ Baker, W. (1933). "Molecular rearrangement of some o-acyloxyacetophenones and the mechanism of the production of 3-acylchromones". J. Chem. Soc.: 1381–1389. doi:.
- ^ Mahal, H. S.; Venkataraman, K. (1934). "Synthetical experiments in the chromone. group. XIV. Action of sodamide on 1-acyloxy-2-acetonaphthones". J. Chem. Soc.: 1767–1769. doi:.
- ^ T. S. Wheeler (1952). "Flavone". Organic Syntheses 32: 72. http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0478. (also in the Collective Volume (1963) 4:478 (PDF)).
- ^ Jain, P. K.; et al. (1982). "A Facile Baker-Venkataraman Synthesis of Flavones using Phase Transfer Catalysis". Synthesis 1982: 221–222. doi:.
- ^ Kalinin, A. V.;Da Silva, A. J. M.;Lopes, C. C.;Lopes, R. S. C.;Snieckus, V. (9 July 1998). "Directed ortho metalation - cross coupling links. Carbamoyl rendition of the baker-venkataraman rearrangement. Regiospecific route to substituted 4-hydroxycoumarins". Tetrahedron Lett. 39 (28): 4995–4998. doi:.
- ^ Kraus, G. A.; Fulton, B. S. Wood, S.H.J.Org.Chem. 1984, 49, 3212
- ^ Reddy, B.P.; Krupadanam, G.L.D.J. Heterocycl. Chem 1996, 33, 1561
- ^ Kalinin, A.V.; Sneckus, V. Tetrahedron Lett. 1998, 39 4999
- ^ Thasana, N.; Ruchirawat, S. Tetrahedron Lett. 2002, 43, 4515
- ^ Santo, C.M.M.;Sliva, A.M.S. Cavaleiro, J. A.S. Eur.J. Org. Chem. 2003, 4575
See also
- Allan-Robinson reaction
- Kostanecki acylation
External links
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