Cyclopentanone 2-cyclohexenone

Mn(TPP)I04 02 + toluene, cyclohexene or cyclopentane Benzaldehyde, cyclohexenone, epoxide, or cyclopentanone Solvent benzene Xlrr = 310-490 nm selective conversion of toluene to benzaldehyde, and cyclopentane to cyclopentanone using C104 the reactions are stoichiometric [159]... 

Pd(OAc)2 to give the cyclohexenone 256. In clavulone synthesis, only the silyl enol ether in 257 reacts with Pd(OAc)2 to give the enone 258 [153]. The dehydrogenation can be carried out with a catalytic amount of Pd(OAc)2 using benzoquinone as the reoxidant. Cyclopentenone (260) is prepared from cyclopentanone (259) by using a supported Pd catalyst under 02 atmosphere [154], The enone 261 is converted to the dienone 263 via the dienol silyl ether 262 [155],... 

Cyclopentenones and cyclohexenones react with 2-hydroxybenzaldehydes in presence of DABCO to afford cyclopentanone- and cyclohexanone-fused 2/7-chromenes (Equation 37) <2004AGE115>. 

Cyclopentanones.4 The adducts 2, obtained by reaction of trimethylstannyl-lithium with cyclohexenone followed by trapping with an electrophile, when treated with a Lewis acid can give rise to cyclohexanones and/or cyclopentanones. TiCl4 tends to give mixtures of both products, whereas trimethylsilyl triflate favors formation of cyclopentanones. Thus the adduct 5 on treatment with TMSOTf provides only the cyclopentanone 6. Reaction of 5 with TiCl4 gives 6 and 7 in the ratio... 

Irradiation of the cyclohexenone (45) gave the cyclopentanone (46) with a very similar mass spectrum (Burlingame et al., 1967). It was proposed that loss of ketene from the molecular ion of (45) occurred via... 

The reaction may include a cyclopropanol intermediate derived from an anion radical, as seen in the reduction of cyclohexenones under Clemmensen conditions to afford ring-contracted cyclopentanones along with cyclohexanone derivatives.Thus the diastereomeric cyclopropanol acetates (12) and (13) can be obtained in different ratios from both (10) and (11) (12/13 = 3 from 10, 12/13 > 100 from 11 Scheme 6). ... 

Both cyclic and acyclic enone systems participate in the (trimethylsilyl)cyclopentene annelation (Table 6). a-Methylene ketones react to form spiro-fiised systems and the intermediates derived from ace-tylcyclohexanone, cyclohexenone and cyclopentanone cyclize to yield S,S- and 6,3-fiised ring systems. ... 

The cyclobutane-cycloalkanone, as well as the cyclobutane-cycloalkane, ring fusion can be cis or trans. In reactions with cyclopcntenone, cis fusion between the cyclobutane and the cyclopentanone ring occurs exclusively whereas with cyclohexenone cis- and t/ww-fused cy-clobutaiie-cyclohexatione rings are obtained. 

Firstly, it was found that 108 forms inclusion complexes with various solvent molecules. In the inclusion complexes with Pr OH, cyclopentanone, 2-cyclopenteno-ne and 2-cyclohexenone, 108 molecules were found to be ordered in a chiral form from measurement of CD spectra in the solid state of the complexes formed. X-ray... 

Under certain conditions less activated ketones (e.g., acetone, cyclopentanone, cyclohexanone, and cyclohexenone) can participate in the reaction with butadiene or iso-prene, ° but more commonly enamine derivatives are anployed. For example, Tsuji reported that butadiene undergoes Pd-catalyzed linear dimerization with trapping by the pyrrolidoyclohexene 126 (Scheme 39) (Pd(OAc)2, PhjP, CH3CN, 80 °C, 3 h) to afford the octadienyl derivative 127 in 66% yield after hydrolysis (aq. HCl, 50 C, 0.5 h). In addition, 22% of the a,a -dialkylated product was isolated. 

The diastereoselectivity observed for the conjugate addition to the nonchelated enone sulfoxide (98a) was improved by the use of diorganomagnesium reagents with DME as solvent. Under the same reaction conditions, nucleophilic additions to the corresponding cyclohexenone (101) proceeded with moderate stereoselectivity, giving cyclohexanones (102) as products with somewhat lower enantiomeric excesses than for cyclopentanones (99b) (Scheme 5.35 and Table 5.4) [99]. It should also be noted that in several cases the addition of a highly complexing additive such as 18-crown-6 served to raise the amount of asymmetric induction by about 20% (Table 5.4). 

What product is formed when cyclopentanone reacts with pent-l-en-3-one in refluxing ethanol with sodium ethoxide, followed by an aqueous acid workup What is the product if cyclohexenone is used in the same reaction with cyclopentanone ... 

Alkyl-2-vinylcyclobutanones undergo acid-catalysed ring expansion via a 1,2-acyl shift to form cyclopentanones. In the absence of the 2-alkyl group, the predominant reaction is a 1,3-acyl shift giving rise to the cyclohexenone (Scheme 16). 

The product selectivity in the reaction of methylene cyclopropanes with alkynes is strongly substituent-dependent the reaction is catalysed by Ni(0)/tris(o-tolyl Iphosphite (eqn.47). The intramolecular hydroacylation of 4-pentenal is catalysed by low valent Co/PPh3 complexes and produces mainly cyclopentanone.Cyclopentenones and cyclohexenones are the products of the intramolecular carbonylation of vinyl iodides (eqn.48). A large variety of heterocycles are accessible the intramolecular Pd catalysed cyclisation of unsaturated a-haloamides. Treatment with base and PdfOAclj/PPhj converts 2,6-dibromo-l,6-dienes into cyclopentanes with exocyclic double... 

---