Cyclopentane, acetyl

Cyclohexene-l,4-dione, 2,3,5-tiichloro-3, 6-bis(l,l-dimethylethyl)- [5-Cyclo-hexcne-1,4-dione, 2,3,5-tnchloio-3,6-dwert-butyl-], 55, 33 Cyclopentadiene, 55, 15,16 Cyclopentane acetyl-,55,25 Cyclopentane 1-cyano-l-phenyl-, 55,94 Cyclopentane methyl-, 55, 62 Cyclopropane, 1-acetyl-l-phenyl-, 55 94... 

Fthanone, I-cyclopentyl- [cyclopentane, acetyl-], 55, 25 Ethyne [Acetylene], 55,100 Ethyne, butylthio- [Acetylene, butylthio-], 55, 102... 

PENTAMETHYL-, 56, 1 Cyclopentane, acetyl-, 55, 25 Cyclopentane, 1-cyano-l-phenyl-, 55, 94 Cyclopentane, methyl-, 55, 62 Cyclopentanol, p-toluene.sulfonate, 55, 112 Cyclopentene, 56, 34 58, 73 2-Cyclopenten-l-one, 2,5-dialkyl-, 58, 62 CYCLOPENTENONES, 58, 56 Cyclopropane, 1-acetyl-l-phenyl-, 55, 94 Cyclopropane, 1, l-dibromo-2,2-diphenyl-, 56,32... 

Cyclopentane, 1-cyano-l-phenyl-, 55, 94 Cyclopentane, methyl-, 55, 62, 112 Cyclopropane, 1-acetyl-1-phenyl-, 55, 94... 

Simultaneously to the synthetic studies described above, our model studies had progressed. Although the synthetic challenge in this part of the project was marginal the structure elucidation of the final products was complicated [41]. Starting material for the syntheses was 1-acetyl-1-cyclopentene (58) which was converted into the frans-cyclopentane rac-59 by a Sakurai reaction and a carbonyl olefination (Scheme 16). The synthesis of czs-cyclo-... 

As discussed in Sect. 3.4, the synthon 20 was prepared from the dibromo-heptonolactone, which in turn was obtained from the cheap commercially available D-g(ycero-D-gM/o-heptono-l,4-lactone (Table 1). The other isomeric dibro-moheptonolactones shown in Table 1, which were prepared from the heptonates, obtained from chain extension of o-mannose and o-galactose, respectively, were also converted into unsaturated bromodeoxyheptonolactones. Finally, we obtained 2-0-acetyl-7-bromo-3,7-dideoxy-D-x7(o-hept-2-enono-l,4-lactone and the corresponding D-/yxo-isomer by the Kiliani extension of o-gulose. These substrates were all cyclized to cyclopentane lactones, stereoisomers of 65 [98]. 

Cyclopentan 2-Brom-l-oxo- V/4,180 Cyclopropan 2-Acetyl-l-brom- E17b, 1241 (COOH - Br)... 

Acetyl- V/lc, 168 l-Formyl-6-methyl- VII/1, 130 Cyclopentan 3-Oxo-l-(2-propinyl)-E19c, 181 (En-on + Allen-SnR3) Cyclopenten 1-Acryloyl- Vll/2a, 436 l-Cyclopropyl-3-oxo-E17b, 1349f. (cycl, En/R —Li + Br —C3H5)... 

Cyclohexan 1,3-Dioxo-2-methyl-2-(1-methyl-1-nitro-ethyl)- E19a, 746 (Dion A Nitro-alkan) Cyclopentan 2-Acetyl-2-(1-methyl-l-nitro-ethyl)-l-oxo- E19a, 1128 (R-X A R-M)... 

Cyclopent b -l,4-benzothiazine 9-Acetyl-12,3,9-tetrahydro- E9a, 475 (3-Ac-2,3-H2 — 1,3-benzo-thiazol-<2-spiro)-cyclopentan/ S02CI2)... 

E7b/2, 483 6-[CH(OR)J-l,2,4-triazin + Acetyl-cyclopentan 2-Ethoxycarbonyl-4-pentyl- E7b/2, 424 [H2C = CH-C(C5H,) = CH-OR + NC-COOR] Pyridin-l-oxid 4,5-Dimethyl-2-(1-hydroxy-cyclohexyl)- E19d,... 

Use of the chiral carbon pool for cyclopentenone preparation is also known. The fungal metabolite terrein [88] was selectively monoacetylated and then reduced with chromous chloride to enone [89]. Acetylation and olefin cleavage with ruthenium tetroxide aiwi sodium periodate led to aldehyde [90], which was readily decarbonylated to [65] (51). An alternative route (52) began with the less common S,S-tartaric acid [91], converted in four steps to diiodide [92]. Dialkylation of methyl methylthiomethyl sulfoxide with [92] gave the cyclopentane derivative [93]. Treatment of [93]... 

Alkyl-2-(2-oxopropyl)cyclopentane-l,3-diones 33 were smoothly converted into 2-acetyl-3-alkylcyclohexane-l,4-diones 34 by treatment with sodium hydroxide in water or sodium methoxide in methanol. Ring expansion results from intramolecular aldol reaction followed by ring opening of the bicyclo[3.1.0]hexane system. ... 

Menthone was elegantly transposed into carvomenthone by the sequence (196)->(197).439 Piperitol was isomerized into isomenthone over cobalt catalysts.440 Piperitone, p-menth-3-en-2-one, and 8,9-dihydrocarvone can by pyrolysed to aromatics that have lost the Pr group in fair yields (30—50%),441 and menthone can be converted into piperitone and other p-menthen-3-ones via bromination and Zn treatment.442 Pulegone on reaction with HOC1 formed 4-chloro-/>-menth-8-en-3-one,448 and O-acetylated dienolates of pulegone have been prepared.444 Carvo-menthene oxide was isomerized to p-menth-1 (7)-en-2-ol, carvotanacetol, and cyclopentane derivatives over solid acids and bases,445 and 6-thiophenoxy-8,9-... 

The O18 exchanges accompanying the pinacol rearrangement in the cyclohexane-1,2-diol and cyclopentane-l,2-diol systems have also been investigated. The pinacolic rearrangement of both cis- (17) and trans-1,2-dimethylcyclohexane-l,2-diol (18) in aqueous acid gives 1-acetyl-methylcyclopentane and a small amount of 2,2-dimethylcyclohexanone... 

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