Kostanecki acylation reaction

Also known as Kostanecki-Robinson reaction. Transformation 1 2 represents an Allan—Robinson reaction (see page 8), whereas 1 3 is a Kostanecki (acylation) reaction ... 

Kojic acid — see also Pyran-4-one, 5-hydroxy-2-hydroxymethyl-, 3, 611 acylation, 3, 697 application, 3, 880 occurrence, 3, 692 reactions, 3, 714, 715 with amines, 3, 700 with phenylhydrazine, 3, 700 synthesis, 3, 810 Kokusagine occurrence, 4, 989 Kokusaginine occurrence, 4, 989 synthesis, 4, 990 Koopmans theorem, 2, 135 Kostanecki-Robinson reaction chromone and coumarin formation in, 3, 819-821 mechanism, 3, 820 flavones, 3, 819... 

R] (a) Hauser, C. R. Swamer, F. W. Adams, J. T. Org. React. 1954, 8, 59. [R] (b) Ellis, G. P., Chromenes, Chromanones, and Chromones from The Chemistry of Hetereocylic Compounds, Weissberger, A. and Taylor, E. C., eds John Wiley Sons, 1977, vol. 31, New York, p.495. Note The author in the former reference refers to the formation of chromones, coumarins, and flavones as the Kostanecki acylation while the latter author calls the formation of chromones and coumarins the Kostanecki-Robinson reaction. 

The Kostanecki-Robinson reaction proceeds through O-acylation followed by a Baker-Venkataraman rearrangement to the 1,3-diketone. Cyclization then yields the chromone. Early evidence was based on the observation that both of the 1,3-diketones (448) and (449) yielded the same chromone on reaction with the appropriate acid anhydride (33JCS1381). Thus, the reactions were considered to proceed through the common intermediate (450 Scheme 159). 

Synthesis.—Application of the Kostanecki-Robinson reaction to 3-acyl-4-hydroxy-2//-pyran-2-one gave a mixture of pyrano[4,3-6]pyran-4,5-diones... 

This reaction is related to the Allan-Robins on Annulation and Kostanecki Acylation in terms of the formation of flavones. In mechanism, this reaction is related to the Fries Rearrangement. 

Koch-Haaf Carboxylations Kochi Reaction Koenigs-Knorr Synthesis Kolbe Electrolytic Synthesis Kolbe-Schmitt Reaction Komer-Contardi Reaction Kostanecki Acylation Krafft Degradation Krapcho Decarbalkoxylation... 

Gripenberg in The Chemistry ofFlavonoid Compounds, Geissman, Ed. (New York, 1962) p 410. Mechanistic studies K. Bowden, M. Chehel-Amiran, J. Chem. Soc. Perkin Trans. II 1986, 2039. Synthetic applications P. K. Jain etal, Synthesis 1982, 221 J. Zhu etal., Chem. Commun. 1988,1549 A. V. Kalinin et al, Tetrahedron Letters 39,4995 (1998) D. C. G. Pinto et al, New J. Chem. 24, 85 (2000). Cf. Allan-Robinson Reaction Kostanecki Acylation. 

---