3168-90-9

Usage

Synthesis Reference(s)

Synthetic Communications, 17, p. 975, 1987 DOI: 10.1080/00397918708063956Synthesis, p. 801, 1983 DOI: 10.1055/s-1983-30519

InChI:InChI=1/C8H12O/c1-6-4-3-5-8(6)7(2)9/h3-5H2,1-2H3

Upstream product

• 1626-09-1 2,7-octanedione 
• 855909-81-8 2,5-diacetyl-adipic acid diethyl ester 
• 110-82-7 cyclohexane 
• 75-36-5 acetyl chloride 
• 693-89-0 1-methylcyclopent-1-ene 
• 2781-29-5 3,4-Dimethyl-hexadien-(1,5)-diol-(3,4) 
• 24395-06-0 CH₃COCH₂CH₂CH₂CCMe 
• 16737-04-5 oct-1-yn-7-one 
• 108-24-7 acetic anhydride 
• 3168-79-4 2,7-dimethyl-4,5-dihydro-1H-azepine-3,6-dicarboxylic acid dimethyl ester 
• 917-64-6 methyl magnesium iodide 
• 59253-86-0 2-methyl-1-cyclopentenecarbonyl chloride 
• 97943-16-3 (E)-2-hexenoyl chloride 
• 96-37-7 methyl-cyclopentane 

Downstream Products

• 3664-75-3 1-acetyl-2,2-dimethylcyclopentane 
• 67209-77-2 2-methyl-cyclopent-1-enecarboxylic acid 
• 1601-03-2 2-Methyl-Δ¹-cyclopentenyl-methyl-keton-semicarbazon 
• 1601-02-1 1-(2-methyl-cyclopent-1-enyl)-ethanone-(2,4-dinitro-phenylhydrazone) 
• 3664-69-5 cis-1-(2-methylcyclopentyl)ethanone 
• 3664-70-8 trans-1-(2-methylcyclopentyl)ethanone 
• 80885-63-8 (E)-2,4,5,7-Tetramethyl-octa-2,4,6-triene 
• 117712-71-7 1-Methyl-2-((E)-1,2,4-trimethyl-penta-1,3-dienyl)-cyclopentene 
• 117712-85-3 C₁₆H₂₄ 
• 122775-31-9 1-vinyl-1-{1-hydroxy-1-(2-methylcyclopent-1-en-1-yl)ethyl}cyclohexane 
• 17190-15-7 2-acetyloxy-2-methylcyclopentanone 
• 145801-12-3 1,2-epoxy-1-acetyl-2-methylcyclopentane 
• 81454-82-2 1-(1-Chloro-2-methylene-cyclopentyl)-ethanone 
• 81454-83-3 1-(1-Chloro-2-methyl-cyclopent-2-enyl)-ethanone 

Relevant academic research and scientific papers

Theoretical Study of Intramolecular Aldol Condensation of 1,6-Diketones: Trimethylsilyl Substituent Effect

Diastereoselective intramolecular aldol condensations are investigated in an experimental and computational study of 1,6-diketones. Ab initio results show the importance of the acid medium and disapprove the possibility of a spontaneous cyclization, even for silylated compounds. The combination of both experimental and computational approaches brings valuable information on the mechanism and on the selectivity of the aldol reaction. It is found that the enolization of the diketone is a key step in acid-catalyzed mechanism. The cyclization step bears a very small activation energy. The dehydration of the aldols are discussed.

Formal total synthesis of (±)-trichodiene via Claisen rearrangement and Robinson annulation

A facile formal total synthesis of (±)-trichodiene was achieved by employing Claisen rearrangement and Robinson annulation as synthetic key strategies.

Iridium complex-catalyzed addition of water and alcohols to non-activated terminal alkynes

The addition of water and alcohols to non-activated terminal alkynes was found to be promoted by an iridium complex combined with Lewis acid and phosphite. Thus, terminal alkynes reacted with water or alcohols to give ketones or ketals, respectively, in good to excellent yields. α,ω-Diyne like 1,7-octadiyne was converted into 1-(2-methyl-cyclopent-1-enyl)ethanone through the intramoleculer aldol condensation of the resulting 2,7-octanedione induced by Lewis acid.

Stereoselective construction of the dicyelopenta[a,d]cyclooctene core of the ceroplastin sesterterpenes by way of the anionic oxy-cope rearrangement

Bicyclo[3.2.1]oetanediones such as 9, which are readily available by double carbonylation of (1,3-cyclohexadiene)iron tricarbonyl complexes according to Eilbracht, are amenable to regiospecific methylenation under Wittig conditions. Reduction of 10 with copper hydride leads to 11, which can be resolved by application of Johnson's sulfoximine technology and oxidized to give the enantiopure antipodes of 10. Variously substituted cyclopentenyl anions undergo 1,2-addition to 10, providing carbinols which are capable of anionic oxy-Cope rearrangement via chair transition states. These structural reorganizations are fully stereocontrolled and lead directly to functionalized dicyclopenta[a,d]cyclooctenes. When 11 is treated analogously, only [1,3] sigmatropy is observed and inversion of stereochemistry at the migrating carbon prevails. Both processes exhibit impressive scaffolding powers and are characterized by brevity.

Hydration of Alkynes in Anhydrous Medium with Formic Acis as Water Donor

Formic acid has been found to hydrate alkynes in the absence of water to give oxo products and carbon monoxide.The scope of the reaction of alkynes and formic acid has been delineated.Hydrocarbon alkynes were found to be reactive in the absence of catalyst.Functionalized alkynes, in particular oxygenated alkynes, are inert toward formic acid but can be activated catalytically with Ru3(CO)12.Consequently, all the tested types of alkynes were found to give oxo products and CO with formic acid.The mechanism of the reaction was examined.With some alkynes, the primary oxo products underwent secondary reactions that gave rise to unexpected products.

Mechanism of the Intramolecular Cyclization of Acetylenic Ketones

Acid-catalyzed intramolecular cyclization of 5-cyclodecynone (1) under a variety of conditions gives bicyclo-1(6)-decen-2-one (6) as the only product.In a recent report, evidence for a reaction mechanism involving transannular triple-bond participation with a polarized carbonyl group followed by attack of the original carbonyl oxygen on the developing vinyl cation to give an unstable oxete intermediate (4) was presented.Subsequently, several workers have suggested a mechanism involving acid-catalyzed enolization of 1, followed by the transannular attack of the enol double bond at the acetylenic function, as the first two steps in an alternate process for explaining this rearrangement.When 6-octyn-2-one (9) was treated with either mineral or Lewis acids, a mixture of 1-acetyl-2-methyl-1-cyclopentene (12) and 2,3-dimethyl-2-cyclohexen-1-one (14) were produced.Experiments have shown that the oxygen atoms in the starting acetylenic ketone 9 are same ones found in the cyclic products 12 and 14.A mechanism involving cyclization of enol intermediates cannot account for the formation of 14.On the other hand, formation and rearrangement of oxete intermediates demonstrates how both 12 and 14 are produced.The results from acid-catalyzed cyclization of 6-octyn-2-one (9) are also compared to those reported for the solvolysis of the tosylate of 6-octyn-2-ol (18).

Acylation of alkenes generated in situ by hydride transfer from isoalkanes. Synthesis of pentalenones, hydrindenones, and cyclopentenones

Acylation, in the presence of AlCl3 and hydride acceptor, of methylcyclopentane, methylcyclohexane, and 2-methylbutane by ethylenic acyl chlorides, in CH2Cl2 solution, respectively, leads to tetrahydropentalenones, tetrahydroindenones, and cyclopentenones in good yields. Hydride acceptor may be either acetyl chloride or the alkenoyl chloride itself. Better results are performed in the presence of nitromethane and CuSO4. Overall yields are better than those obtained by the two-step process involving acylation of alkenes by alkenoyl chlorides and subsequent Nazarov cyclization of the resulting divinylketones. Methyl 1,4-migration is observed during the acylation of 2-methylbutane by sorboyl chloride. The mechanism of these conversions is discussed on the basis of results observed with cyclohexane-d12 and methylbutane-d6 as well as stereochemical studies of the cyclization process.

Synthesis with Organoboranes; 4. Transformation of Olefins into Homoallylic Alcohols, β,γ- and α,β-Unsaturated Ketones via Allylic Diethylboranes

Allylic diethylboranes are obtained from 1-methylcycloalkenes and 2-alkenes, respectively, via metalation with trimethylsilylmethylpotassium (generated in situ from bis(trimethylsilylmethyl)mercury and potassium sand) and subsequent reaction with chlorodiethylborane.The allylic boranes react diastereoselectively with aldehydes to give homoallylic alcohols.The alcohols are oxidized with pyridinium dichromate to β,γ-unsaturated ketones, which in turn are isomerized with aluminum oxide to conjugated ketones.The transformation provides access to 2-methylene-1-acylcycloalkanes, 3-acyl-1-alkenes and 3-acyl-2-alkenes not readily available by Friedel-Crafts acylation of olefins.

Cyclisation de composes acetyliniques carbonyles via leur ether d'enol silyle: II. Synthese et reactivite de quelques ethers d'enols derivees d'aldehydes ou de cetones acetyleniques terminaux

A number of silyl enol ethers of ω-acetylenic ketones or aldehydes have been prepared following various literature procedures which are compared to each other.By treatment with mercury (II) chloride (1.1 equiv.) in the presence of HMDS (0.2 or 1.5 equiv.) at room temperature, followed by acidification with aqueous HCl-NaI, silyl enol ethers 1, 2, 3, 9, 11, 12 and 13 are cyclized in high yield into 2-alkylidene-1-oxocyclopentanes, methylene- spiro or poly-cyclanones, a methylene cyclopentane unit being formed in the reaction.In the same way, from silyl enol ethers 4, 8 and 10 a methylenecyclohexane unit is formed.In all the products the exocyclic position of the C=C double bond so formed is fully maintained.