Cyclanones

Fusion of SIX membered nngs by reactnn of cyclanones with vinyl ketones (base or acd catalyzed), a tandem Michael addition aldol condensation... 

Dicyano-substituted triafulvenes react with enamines to produce exclusively the cross-conjugated dicyanomethylene compounds 519, whose formation can be rationalized by a methylene bicyclo(2,l,0)pentane intermediate 51879 296 Since cyclanone enamines 520 and other cyclic enamines 522 react analogously, this C-C-insertion 237) of the triafulvene ring skeleton into the enamine C=C bond represents a versatile ring expansion mode (C + C3), which makes accessible a series of unsaturated medium-ring compounds (521/523) that are otherwise difficult to synthesize. 

Durch eine Analyse konkurrierender Energietibertragungen 19> vom elektronen-angeregten Cyclanon auf geeignete Loscher (Quencher) ist... 

Abb. 3. Das erste bekannt gewordene Beispiel einer lichtinduzierten Ringerweiterung eines Cyclanons zum entsprechenden Oxacarben, das in Gegenwart hydroxyl-gruppen-haltiger Losungsmittel zu Acetalen reagiert 25>... 

Abb. 14, Korrelationsdiagramm fur die a-Spaltung eines Cyclanons die Orbitale 7Cz und %z sind die senkrecht zur Papierebene stehenden eigentlichen" 7i-Orbitale der Carbonylgruppe... 

Fig. 29. Dependence of half-wave potentials of cyclanones (1) their betainyl hydra-zones (3) and l-piperidinomethyl-2-cycloalkanones (2) on half-wave potentials of cycloalkyl bromides. Full points deviate...

Wladislaw, B., Bueno, M.A., Marzorati, L., DiVitta, C. and Zukerman-Schpector, J. (2004) Phase transfer catalysis (PTC) sulfanylation of some 2-methylsulfinyl-cyclanones. J. Org. Chem., 69, 9296. 

From the sequential reaction of 4-chromanones 251 with thionyl chloride, thioacetic acid, and morpholine, a mixture of thioxochroman-4-one 252 and its. Y-sulfide 253 can be obtained (actually they can disproportionate). By cycloaddition, stereoisomeric 1,2,4-trithiolane derivatives 254 and 255 have been obtained the R1, R2 groups in Scheme 78 can actually be derived from cyclanones < 1998JOC9480>. 

Selective hydrolysis by sulfuric acid is also observed in the formation of 2-(5-aryl-l,2-dithiol-3-y]idene)cyclanones from the corresponding trithiapentalenes, in low yield.27... 

Reaction of phosphorus pentasulfide with j3,8-triketones leads to l fiayS -trithiapentalenes.1,2-8> 52 This was the first synthesis of trithiapentalenes known, but its development was delayed until practical methods for preparing 3,8-triketones were available. One of these procedures is the acylation of ketones in the presence of sodium hydride.53 Another method begins with the diacylation of the enamine derived from a cyclanone.38... 

Anions (35) are easily methylated by methyl iodide, giving 38. With medium-sized cyclanones (C5 to C8), the formation of 37 is not possible,55 but with larger rings the thiopyrones can be obtained.58 When the tetrakisalkylthio compound (38) is reacted with phosphorus pentasulfide, a bis(alkylthio)trithiapentalene is formed.55... 

According to their structure, a-(l,2-dithiol-3-ylidene) ketones are more or less easily protonated. This protonation is often effected by perchloric acid and a crystallized perchlorate may be obtained. This has been observed with dithiolyliophenolates20, 81,33 and various a-(5-aryl-l,2-dithiol-3-ylidene)cyclanones.13,21,27... 

It has been shown that the formation of -phenylselanyl enoxysilanes, from a-phenylselanyl cyclanones, is not regioselective even by in situ quench of the enolate with chlorotrimethylsilane and despite the more acidic character of the C-H bond of the selenenylated carbon [40] (Scheme 34). 

Reaction of an a-(phenylthio)nitrile with base, such as LDA, followed by an aldehyde or a ketone gives a 1,2-addition product in good yield, while the use of a, -unsaturated aldehy s and ketones usually leads to the 1,4-addition product. Conjugate addition of the a-(phenylthio)acetonitrile anions to 2-methyl- or 2-phenyl-2-cyclohexenones or 2-methyl-2-cyclopentenones, followed by acid quenching under kinetic control, leads to different ratios of cis and rr[Pg.561]

Lacoume, B., Milcent, G., Olivier, A. Regioselectivity in the Fischer indole synthesis using 3-substituted cyclanones. Tetrahedron 1972, 28, 667-674. 

When using Cyclanon ECO, the reductive cleaning is performed in the exhausted dye bath itself without changing the pH. After completion of the reductive step one additional rinsing bath is sufficient to complete the process. 

We condensed a lot of cyclanone enolates with various ring size and numerous cyclohexanone enolates substituted in various positions by alkyl groups63,68,69,70. From all this work we can make the following practical remarks ... 

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