2,4-HEPTANEDIONE, 3-METHYL

HEPTANEDIONE, 3-methyl-, 55, 127 Heptanenitrile, 2-ethenyl-2-phenyl, 55, 102 Heptanenitrile, 2-phenyl-, 55, 102 Heptanoic acid, 4-oxo-, ethyl ester... 

Sabinene is a monoterpene found in the oil of citrus fruits and plants It has been synthe sized from 6 methyl 2 5 heptanedione by the sequence that follows Suggest reagents suitable for carrying out each of the indicated transformations... 

SULFIDE CONTRACTION via ALKYLATIVE COUPLING 3-METHYL-2.4-HEPTANEDIONE... 

C. 3-Methyl-2,i-heptanedione. A dry, 500-ml., three-necked, round-bottomed flask equipped with a magnetic stirring bar, a pressureequalizing dropping funnel, a thermometer, and a condenser fitted with a nitrogen-irdet tube is charged with 17.8 g. (0.20 mole) of anhydrous lithium bromide (Note 21). Under- a nitrogen atmosphere, 34.8 g. (0.20 mole) Of -(2-oxobut-3-yl) butanethioate dissolved in 120 ml. of anhydrous acetonitrile (Note 22) is added to the flask. 

METHYL-2,4-HEPTANEDIONE, 55, 127 3-Methyl-3-heptyl alcohol, 58, 78 3-Methyl-4-heptyl alcohol, 58, 78 3-Methyl-3-heptyl fluoride, 58, 78 3-Methyl4-heptyl fluoride, 58, 78 7V-(4-Methyl-2,4-hexadienoyl)pyrolidine,... 

This procedure represents a novel, convenient, and fairly general method for preparing y-aryl-/3-diketones. By this method the submitters have phenylated the dianion of 1-phenyl-1,3-butanedione (61%), 2,4-heptanedione (98%), 2,4-nonanedione (78%), 2,4-tridecanedione (53%), and 3,5-heptanedione (50%).6 Substituted diaryliodonium salts have also been used to produce l-(4-chlorophenyl)-2,4-pentadione (44%), 4-(4-methyl-phenyl)-l-phenyl-l,3-butanedione (44%), and l-(4-methyl-phenyl)-2,4-nonanedione (21%).6 Under these conditions no more than a trace, if any, of arylation at the a-position of the /3-diketones was observed by gas chromatography analysis. 

Several /3-diketonate complexes of the type [W(L-L)X2] (X = Cl, Br L = acac, 6-methyl-2,4-heptanedione, dibenzoylmethane) have been prepared from reaction of the j8-diketone ligands with WX5. The suggested cis stereochemistry, based on IR measurements, must be considered tentative. 

Product A, which has two singlet methyl groups and no vinylic protons in its HNMR, is the major product of the intramolecular cyclization of 2,5-heptanedione. 

Miyanaga [2] prepared moderate molecular weight polyglycidol ethers, (II), by polymerizing the corresponding glycidol ether with samarium triisopropoxide, samarium tris(tetramethyl heptanedionate), and yttrium tris(tetramethyl hep-tanedionate) with methyl aluminoxane. 

Since EIMS is suitable only for relatively volatile materials, most metals must be converted to volatile chelates before they can be analysed by this technique. The magnesium chelate found most amenable to EIMS is the diketonate Mg(2,2, 6,6 -tetra-methyl-3,5-heptanedione)2 (Mg(THD>2) (19). The chelate can be formed in aqueous solutions at pH >9 in the presence of excess THD (16). Extraction into ethyl ether provided a simple method for separating the chelate from excess THD which otherwise interferes in the MS analysis of Mg(THD)2 The ether layer was transferred to a 10 ml glass tube and allowed to stand at room temperature. 

Problem 24.11 Draw a stepwise mechanism for the conversion of 2,6-heptanedione to 3-methyl-2-cyclohexenone with NaOEt, EtOH. 

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