Cyclopentan-1,3-dione, 2-ethyl

A modification of this method utilizes the direct conversion of l,2-bis(trimethyl-siloxy)cyclobutene in one step to 2,2-disubstituted cyclopentane-1,3-diones. For example, 2-ethyl-2-methylcyclopentane-l,3-dione (3) was obtained in 91% yield from 1.2-bis(trimethyl-siloxy)cyclobutene and butan-2-one 2,2-dimethylpropane-l,3-diyl acetal.41 Further examples... 

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)... 

Methylethyl) cyclohexadiene-1 -ethyl formate. See4-(1-Methylethyl) cyclohexadiene-1-ethanol formate (1-Methylethyl) cyclohexane. See Isopropylcyclohexane (1-Methylethyl) cyclopentane. See Isopropylcyclopentane Methyl ethyl diketone. See Pentane-2,3-dione Methylethyl disulfide. See Diisopropyl disulfide 1-Methylethyl docosanoate. See Isopropyl behenate... 

Spirocyclopentene-l,3-diones. A soln. of ethyl cyclobutanecarboxylate in THF treated with 1.1 eqs. LDA followed by 3-phenylthiopropanal at —78, and after 1 h the resulting hydroxythioether oxidized with 1.1 eqs. NaI04 methanol for 10 h at 0" - intermediate sulfinylester (Y 61 %), in THF treated with 3-3.3 eqs. LDA at —78° for 1 h and at 0° for 1-2 h - intermediate spiroketone (Y 88%), treated with 8 eqs. pyridinium chlorochromate in methylene chloride at room temp, for 20 h - product (Y 65%). F.e., inch spiro-cyclopentane, -cyclohexane, and -l-indane analogs, also isolation of 2-spirocyclopent-4-en-3-olones, s. M. Pohmakotr et al.. Tetrahedron Letters 30, 1715-8 (1989). 

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