Baker-Venkataraman reaction

A ring closure that is often associated with the reaction is called the Baker-Venkataraman Reaction. N. Thasana, S. Ruchirawat, Tetrahedron Letters 2002, 43, 4515... 

The base-catalysed acyl transfer (Baker-Venkataraman reaction) of enantiopure 2-acetyl-l-hydroxyanthraquinone esters of 2-methylbutanoic acid or of O-allyllactic acid produces the respective 1,3-diketones, precursors of anthra[l,2-fc]pyran antibiotics, without any racemization.9... 

Trifluoromethyl derivatives of thiochromone are also available from thiosalicylic acid by conversion to alkyl 2-mercaptophenyl ketones followed by a Baker-Venkataraman reaction with trifluoroacetic anhydride in triethyl-amine (Scheme 205) <2005PS(180)1315>. 

The value of l-(o-hydroxyphenyl)-3-arylpropane-l,3-diones in the synthesis of O-heterocycles by the Baker-Venkataraman reaction with aroyl chlorides has been exemplified by their conversion into 3-acylflavones, flavones, flavanones and... 

Nencki reaction conditions, followed by partial methylation, phase-transfer catalyzed Baker-Venkataraman reaction with veratroyl chloride, and photocyclization. An outline of this method is depicted in Scheme 8. 

Scheme 2.130. Domino reaction involving a Baker-Venkataraman rearrangement to afford 2-579.

One-pot conversions of 2-hydroxy(acylbenzenes) with anhydrides or acid chlorides to produce coumarins [52-54] and flavones [54-58] under mild liquiddiquid or solidtliquid two-phase conditions via a Baker-Venkataraman type reaction (Scheme 6.19) are catalysed by quaternary ammonium salts. 3-Substituted coumarins are produced from salicylaldehyde and malonodinitrile, or substituted acetonitriles, in high yield (>85%) in a one-pot catalysed sequential aldol-type reaction and cycliza-tion in the absence of an added organic solvent [59]. When 2 -hydroxychalcones are reduced under catalytic two-phase conditions with sodium borohydride, 2,4-cis-flavan-4-ols are produced [60] (see Section 11.3). 

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). 

A highly efficient and operationally simple domino reaction was developed in the laboratory of S. Ruchiwarat for the synthesis of benz[h]indeno[2,1-e]pyran-10,11-diones. The initial aroyl-transfer was achieved by the Baker-Venkataraman rearrangement by subjecting the starting material to KOH in pyridine under reflux for 30 minutes. 

Bowden, K., Chehel-Amiran, M. Reactions of carbonyl compounds in basic solutions. Part 11. The Baker-Venkataraman rearrangement. J. 

Related reactions Dieckmann condensation, Baker-Venkataraman rearrangement ... 

A brief survey (5 papers from 1933 to 1950) was given and the conditions of Baker-Venkataraman rearrangement were investigated elsewhere (equation 111). It was found that sodium ethoxide in benzene was the best catalyst for this reaction. It was also shown that this rearrangement failed in the case of the ester 244. 

This reaction is closely related to the Baker-Venkataraman Rearrangement and Kostanecki-Robinson Reaction. Regarding the synthesis of flavone derivatives, the Allan-Robinson condensation is also related to the Algar-Flyn-Oyamada (AFO) Reaction and Auwers Synthesis. 

This reaction is related to the Allan-Robinson Annulation and Baker-Venkataraman Rearrangement. 

Baker-Venkataraman rearrangement 338 Balaban synthesis (pyrylium ion) 302 Bamberger-Hughes-Ingold rearrangement 350 Barton-Zard synthesis (pyrrole) 120 Batcho-Leimgruber synthesis (indole) 136 Baylis-Hillman reaction 452 Beirut reaction 254, 500 Bemthsen synthesis... 

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