2-Methyltetrahydrofuran-3-one

Consider a small amount of monomer added to the glasses the reaction of monomer with the electrons and that with the cation radicals are thought to prevail in the glasses of 2-methyltetrahydrofuran and n-butylchloride, respectively. In the 3-methylpentane glass, whether the anionic reaction and/or the cationic one occurs depends on the nature of the monomer. 

There are few studies that compare two or more of the group 2 metal enolates. One is an ESR study of the bis(semidione) of l,l,4,4-tetramethyltetralin-2,3-dione (8) where M = Be +, Mg +, Ca +, Sr +, Ba + and Zn +, and the analogous tris-complex of AP in frozen solutions of 2-methyltetrahydrofuran. Be, Ba and Zn form only one kind of complex 8, while there are four types for Mg + and Ca and three types with Sr +. AU group 2 cation complexes are in their triplet state that of A1 is likely a quartet-state complex. Another study discusses the use of the rhodizonate ion (3) as reagent for the detection of Sr +, with stronger enolate-metal binding than with and Ba ... 

Two criticisms of this mechanism can be made. First, these activation energies are overall activation energies for a two-step process for the decomposition of different alkylperoxy radicals [106] see opposite page. For the formation of 2-methyltetrahydrofuran both steps will involve cyclization and will have pre-exponential factors [104] of ca. lO sec", whereas the formation of pent-2-ene involves only one such step and a second step for which [39] A = 10 sec". Since the strain energy involved in the isomerizations of each of the alkylperoxy radicals is the same (ca. 6.5 kcal. mole" ) the activation energies of this step will only differ by the difference in primary and secondary C—H strengths (ca. 3.5 kcal. mole" ). It is difficult, therefore, to see how the overall activation energies for the formation of pent-2-ene and 2-methyltetrahydrofuran can be approximately equal. 

Methyltetrahydrofuran see 2-Methyloxolane Methyl 4-toluate see Methyl 4-methylbenzoate Methyl valerate see Methyl pentanoate Methyl vinyl ketone see But-3-en-2-one MIBK see 4-Methylpentan-2-one... 

Pentacarbonyliron catalyzes the [4 -F 1]-cycloaddition of CO to allenyl ketones and allenyl aldehydes in high yields and with good stereoselectivity. This reaction was examined in 2-methyltetrahydrofuran (2-MeTHF) matrices where the substituted complex Fe(CO)4(2-MeTHF) was found to be produced upon photolysis of Fe(CO)s at 190-230 K. When Fe(CO)s was photolyzed at 230 K in 2-MeTHF in the presence of 5-methyl-3,4-hexadien-2-one and CO, the corresponding a-alkylidene butenolide was obtained (Scheme 4). The reaction proceeded via a dissociative process from Fe(CO)4(2-MeTHF). ... 

Anti syn diastereomer ratio. b % Ee of the anti diol. c A mixture of did and 6-lactone. d (3/ ,5S)-3-Hy-droxy-5-methyltetrahydrofuran-2-one. 

Hydrogenation of ethyl 2,4-dioxopentanoate with an (S)-MeO-BIPHEP-Ru complex followed by in situ cyclization gives (3R,5S)-3-hydroxy-5-methyltetrahydrofuran-2-one with 98% ee and the 3R,5R isomer with 87% ee in an 84 16 ratio [236]. Ethyl 2-hydroxy-4-oxopentanoate is the only detectable intermediate. 1,3-Diphenyl-l,3-propanediol with a BIPHEMP-Ru complex is transformed to an anti-diol selectively [237]. 1,5-Dichloro-2,4-pentanediol, a versatile chiral building block, is selectively obtained through the BINAP-Ru catalyzed hydrogenation of a... 

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