Cyclic /J-diketones

Synthesis of carboxylic acids from carboxylic acid chlorides via cyclic j -diketones and ketocarboxylic acids—Ghain extension by 6 G-atoms s. 13, 810 by 5 and 10 G-atoms, ring opening with dil. NaOH, s. B. 93, 913 (1960)... 

Cyclic j -diketones from ketocarboxylic acid esters. Diethyl a-methyl-a-acetyl-glutarate in dry ether added dropwise with stirring to a suspension of alcohol-free K-ferf-butoxide in dry ether, and refluxed 3 hrs. -> ethyl l-methyl-2,4-dioxocyclohexane-l-carboxylate. Y 70.4%. S. M. Mukherji, R. K. Sharma, and O. P. Vig, Soc. 1958, 4770. 

Alkylution of cyclic I J-diketones The reaction of cyclic 1,3-diketones with thallium(l) ethoxidc, thallium(l) carbonate, or thallium(l) cyclopentadienide gives colorless, crystalline thallium(l) salts (2,408). These salts can be alkylated in nonpolar solvents (benzene, DME) to give products of O-alkylation in high yield, as illustrated... 

P-Diketone substrates have been valuable in the aza-annulation reaction with a,(J-unsaturated carboxylic acid derivatives, and both acyclic and cyclic (i-diketone species have been investigated. The simplest acyclic P-diketone, 150, underwent condensation reaction with BnNH2 to generate the... 

Amarp, J., J. Bielawski, B.M. Dahlin, O. Dahhnan, C.R. Enzell, and T. Pettersson Cyclic a-diketones found in cigarette smoke condensate 44th Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 44, Paper No. 65, 1990, p. 45. 

Cyclic 2-acyl-j -diketones from dicarboxylic acid esters... 

J. Quiroga, S. Portillo, A. Perez, J. Galvez, R. Abonia, B. Insuasty, An efficient synthesis of p)frazolo[3,4-i ]pyridine-4-spiroindolinones by a three-component reaction of 5-aminopyrazoles, isatin and cyclic p-diketones, Tetrahedron Lett. 52 (2011) 2664-2666. 

For regiospecific alkylation of kinetic enolates of cyclic /3-diketone enol ethers, see G. Stork and R. L. Danheiser, J. Org. Chem., 38, 1775 (1973). 

Just recently, a cyclo-cyanosilylation has been described321. Ryu and his coworkers have taken dicyanodimethylsilane (J>43)310) as a reagent under the conditions of the common cyanosilylation and obtained cyclic silyl enol ether (544,545) when (S-hydroxyketones or j8-diketones were employed (Scheme 87). 

Grogan, G., Graf, J., Jones, A., Parsons, S., Turner, N. J. and Flitsch, S. L An asymmetric enzyme-catalyzed retro-Claisen reaction for the desymmetrization of cyclic diketones. Angew. Chem. 2001,113 1145-1148 [Angew. Chem. Int. Ed. 40 1111-1114]. 

Quiroga J, Trilleras J et al (2010) Microwave-assisted synthesis of pyrazolo[3, 4-b]p5Tidine spirocycloalkanediones by three-component reaction of 5-aminopyrazole derivatives, paraformaldehyde and cyclic / -diketones. Tetrahedron Lett 51 4717 719... 

Gupta O D, Twamley B, Shreeve J M. Perfluoro alkyl 1,3-diketonates of cyclic and acyclic secondary amines. J. Fluorine Chem. 2006. 127, 263-269. 

D.J. Burnell et al. synthesized bicyclic diketones by Lewis acid-promoted geminal acylation involving cyclic acyloins tethered to an acetal. The required b/s-silyloxyalkenes were prepared by using the standard acyloin condensation conditions. ... 

In the presence of Mn(OAc)3- 2ll,() in AcOH, allyltrimethylsilane reacts with 1,3-diketones and /I-ketoesters to give trisubstituted dihydrofurans in good to high yield (Scheme 10.187) [502], Mn(OAc) j serves as an oxidizing agent to generate an electrophilic carbon radical intermediate from the substrate. It is probable that annulation of the carbon radical with the allylsilane followed by oxidation with another equivalent of Mn(III) forms the silicon-containing cyclic products. 

With strains of Saccharomyces the (25,35)-isomer is produced predominantly, accompanied by some of the (2/J,3,S )-isomer. Similar to ft-keto esters, the formation of the undcsired isomer can be decreased by the addition of an a,/i-unsaturatcd carbonyl compound, e.g.. methyl vinyl ketone, or an allylic alcohol. These additives probably act as inhibitors for the enzyme which produces the (2/ ,35)-isomer202 203. More recently, the microbial reduction of a variety of simple 2,2-disubstituted cyclic 1,3-diketones of various ring size has been investigated204 205 206. In most cases one of the substituents in the 2-position is methyl. The configuration of the hydroxy group in the reduced product is always S, and the enantiomeric excess is often high (Table 7). 

Condensation reactions on nickel(II) matrices are sensitive to steric effects. X-Ray structm analysis showed [310, 320-328] that H2L263 and its metal complexes are saddle-like, rather than planar. The sources of structural nonplanarity are steric repulsions between methyl groups R, 4 and orr/K>-aromatic protons of the Schiff bases. The increase in the bulk of the groups in these positions hinders macrocyclisation. For example, 3,5-heptanedione, 4,6-nonanedione and 1-phenyl-2,4-pentanedione form cyclic products [Ni(L274)]-[Ni(L276)J, whereas dibenzoyl-methane, 2,6-dimethyl-3,5-heptanedione and 2,2,6,6-tetramethyl-2,5-heptanedione do not give macrocyclic compounds in the presence of nickel(II) and o-phda [300, 320]. In the case of dibenzoylmethane, the nickel(II) )ff-diketonate bis-diamine adduct is isolated (Eq. 2.164) [319]. 

In the syntheses of the second group, the formation of the AD fragments takes place by the reaction of cyclic 1,3-diketones with Mannich bases containing ring A and a side chain with the potential Cg-Cg, C j, and atoms (Schemes 53 and 54). In the third group of syntheses, the formation of rings B and C takes place in the diene condensations of bicyclic dienynes with maleic anhydride and some of its derivatives (Scheme 55). 

Presset M, Coquerel Y, Rodriguez J. Microwaves-assisted Wolff rearrangement of cyclic 2-diazo-l,3-diketones an eco-compatible route to a-carbonylated cycloalkanones. J. Org. Chem. 2009 74 415-418. 

Trost BM, Dong G, Vance JA. Cyclic 1,2-diketones as core building blocks a strategy for the total synthesis of (—)-ter-pestacin. Chem. Eur. J. 2010 16(21) 6265-6277. 

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