Bicyclo 2.2.2 octane-2,6-dione

Five coordinate germanium(IV) complexes l,l,5-trimethyl-2,8-dioxa-5-aza-l-germa-bicyclo [3.3.01,5]octane diones (163) can be prepared from the reaction of R2GeX2 (R = Me, Ph X = C1, OR) with MeN(CH2C02H)2." Tridentate ligand 5-aza-2,2,8,8-tetramethylnonane-3,7-dione reacts with tin(IV) chloride to form (164), comprising a tin(II) center which is liable to oxidation by SO2CI2 to form (165)." ... 

Bicyclo[3.3.0]octane-4,8-dione, 2,6-diaryl-3,7-dioxo-synthesis, 4, 695 Bicyclo[4.4.0]pentaborazane nomenclature, 1, 25 Bicyclo[2.1,0]pentasilane nomenclature, 1, 25... 

The formation of bicyclo[3.3.0]octane-3,7-diones 3 by reaction of an a-diketone... 

Scheme 13.17 depicts a synthesis based on enantioselective reduction of bicyclo[2.2.2]octane-2,6-dione by Baker s yeast.21 This is an example of desym-metrization (see Part A, Topic 2.2). The unreduced carbonyl group was converted to an alkene by the Shapiro reaction. The alcohol was then reoxidized to a ketone. The enantiomerically pure intermediate was converted to the lactone by Baeyer-Villiger oxidation and an allylic rearrangement. The methyl group was introduced stereoselec-tively from the exo face of the bicyclic lactone by an enolate alkylation in Step C-l. 

Friberg, A., Johanson, T., Franzen, J. etal. (2006) Efficient bioreduction of bicyclo[2.2.2]octane-2,5-dione and bicyclo[2.2.2]oct-7-ene-2,5-dione by genetically engineered Saccharomyces cerevisiae. Organic and Biomo-... 

The present procedure is simpler than others previously described and gives equally good yields. It is easily adapted to the preparation of large quantities of either the diester or the diketone. It can be extended to the preparation of various alkylated 1,4-cyclohexanediones and bicyclic diketbdicarboxylic esters such as diethyl bicyclo[2.2.2]octane-2,5-dione-l,4-dicar-boxylate. 1,4-Cyclohexanedione is a useful intermediate for... 

The preparation of bicyclo[3.3.0]octane-2,6-dione has been accomplished by intermolecular reactionsintramolecular reactions,and degradation... 

McKervey and coworkers have developed an elegantly simple pathway for the conversion of m-bicyclo[3.3.0]octane-2,6-dione to (C2)-C2o-hexaquinane diketone 858 (Scheme CII) Twofold cyclopentenone annulation and hydrogenation rapidly led to the tetraquinane 857. Repetition of the same steps then afforded 858, the x-ray analysis of which showed the molecule to have an opened out conformation as the direct result of severe intramolecular overcrowding. 

Asymmetric elimination in the -hydroxy sulfoximine of bicyclo[3.3.0]octane-2,5-dione monoethylene ketal 3, which is obtained in high yield and diastereoselectivity by addition of (S)-.S -lithiomethyl-A -methyl-S-phenylsulfoximine7, 72 to the latter, by sequential treatment with chlorotrimethylsilane and butyllithium, gives the diastereomeric alkenylsulfoximines (S1)-( )- and (Sy(Z)-4 in a ratio 98 273. 

Nearly all examples of epoxidation of alkylidenecyclobutanes involve 3-chloroperoxybenzoic acid.15 58-70 This is because the conditions are mild, the workup is easy and few byproducts are formed. Generally, dichloromethane or chloroform is used as solvent. Solid sodium hydrogen carbonate is occasionally added to avoid acid-catalyzed rearrangement of the spiro compound. For example, 6-isopropylidene-l,4,4-trimethylbicyclo[3.2.0]heptan-3-one reacted with 3-chloroperoxybenzoic acid and sodium hydrogen carbonate to give 2,2,3, 3, 6-pentamethyl-spiro[3-oxabicyclo[4.2.0]octane-8,2 -oxirane]-4-one (4) in quantitative yield. However, without the use of sodium hydrogen carbonate, substantial amounts of 2,2,6,9,9-pentamethyl-3-oxa-bicyclo[4.3.0]nonane-4,8-dione (5) and 2,2,6,8,8-pentamethyl-3-oxabicyclo[4.3.0]nonane-4,9-dione (6) were also formed.15-64... 

The central bond of bicyclo[4.2.0]octane-l,6-diol was cleaved by potassium periodate in water at room temperature to yield cyclooctane-1,4-dione.156... 

Steven H. Ber z, James M. Cook, Ali Gawlsh, and Ulrich Weiss 27 CONDENSATION OF DIMETHYL 1,3-ACETONEDICARBOXYLATE WITH 1,2-DICARBONYL COMPOUNDS cis-BICYCLO[3.3.0]OCTANE-3,7-DIONES... 

Methylblcyclo[2.2.2]octane-2,6-diane Bicyclo[2.2.2]octane-2,6-dione,... 

Bicycloi3.3.0 octane-3,l-dione derivatives. The condensation of this reagent with 1,2-dicarbonyl compounds in an alkaline medium to give this ring system was reported some time ago1 and has since been explored in detail, mainly by Cook and Weiss.2 Detailed directions are now available for preparation of bicyclo[3.3.0]octane-3, 7-dione from glyoxal and that of the 1,5-dimethyl derivative from biacetyl (equation I).3 The condensation is applicable to a variety of diketones and yields are generally > 60%. It has been used for preparation of several natural products such as isocomene (2).4... 

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