Robinson 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... 

Although the literature refers to the formation of chromones/coumarins as the Kostanecki reaction (and often the Kostanecki-Robinson reaction) and the synthesis of flavones as the Allan-Robinson reaction, others have chosen to merge the two reactions and refer to both transformations as the Kostanecki-Robinson reaction. This section will follow the latter school of thought, and use the Kostanecki-Robinson (K-R) nomenclature. 

Over the years the literature is filled with examples where the initial characterization was incorrect. One example is illustrated below. In 1940, Sethna and Shah presumed that they synthesized coumarins 42 and 43 from a reaction between P-orcacetophenone (44) and its 4-0-methyl ether 45 under standard Kostanecki-Robinson conditions, respectively. Three decades later Bose and Shah synthesized coumarin 43 via another route and concluded that the initial assignment made by Sethna and Shah was incorrect. After the Bose and Shah findings were published, Ahluwalia and Kumar concluded that the Sethna and Shah products were actually chromones 46 and 47 based on proton NMR data and chemical derivatization. Despite these shortcomings, the Kostanecki-Robinson reaction remains an effective method for formation of both coumarins and chromones. 

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. 

Condensation of 2,4-dihydroxypropiophenone (172) with benzoyl chloride and sodium benzoate goes to afford chromone 174, probably via ester 173. This procedure is known as the Kostanecki-Robinson reaction Methylation (175) of the remaining phenolic function by means of dimethyl sulfate, followed by reaction... 

Yohimbenone (370) has been synthesized by Kline (212) via the Robinson reaction of the 374 tetracyclic compound with 4-diethylaminobutan-2-one methiodide, followed by hydrolysis and decarboxylation of intermediate 375. 

Kametani and his collaborators presented two different approaches for the synthesis of ( )-yohimbine and ( )-p-yohimbine 223-226). The first one (223, 224) utilizes Stork s method for the Robinson reaction of the enamine derived from octahydroindolo[2,3-a]quinolizin-2-one (414) to produce 15,16-didehydroyohimbinone (410), prepared first by Szantay et al. (74, 221). 

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 ... 

Limberakis, C. Kostanecki-Robinson Reaction In Name Reactions in Heterocyclic Chemistry, Li, J. J. Corey, E. J., Eds. Wiley Sons Hoboken, NJ, 2005, 521—535. (Review). 

Several older syntheses are based on o-hydroxyacetophenones but these routes generally offer little or no advantage over other methods. The Reformatsky reaction has been used to prepare 3- and 3,4-substituted coumarins (44JIC109) and the Kostanecki-Robinson reaction may yield coumarins instead of or as well as the chromone (see Section 2.24.3.4.1 for further discussion). 

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). 

The annelation process in the Robinson reaction can also be carried out in a stepwise mode, so the alcohols from the aldol condensation step are often obtained (e.g., Scheme 5.17).63... 

Allan-Robinson reaction. Preparation of fla-vones or isoflavones by condensing o-hydroxyaryl ketones with anhydrides of aromatic acids and their sodium salts. 

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... 

A unique reaction that produces a new ring containing an ,p-unsaturated ketone is the Robinson reaction. When an enolate derived from a ketone reacts with methyl... 

This reaction is related to the Auwers Synthesis, Baker-Ollis Reaction, Kostanecki-Robinson Reaction dcnd Allan-Robinson Annulation. 

This reaction was first reported by Allan and Robinson in 1924. It is the synthesis of fiavones or isoflavones derivatives by means of the condensation between o-hydroxyaryl ketones and an anhydride of aromatic acid in the presence of the sodium salt of corresponding acid in the anhydride. Thus this reaction is known as the Allan-Robinson condensation, Allan-Robinson s flavone synthesis, Allan-Robinson reaction, and Allan-Robinson synthesis. ... 

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