- Metal chloride-promoted aldol reaction of α-dimethylsilylesters with aldehydes, ketones, and α-enones
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In the presence of a catalytic amount of LiCl, α-dimethylsilylesters (α-DMS-esters) 1 smoothly reacted with various aldehydes at 30°C to give aldols in good to high yields. On the other hand, the aldol reaction with ketones was effectively promoted by MgCl2 rather than by LiCl. α-Enones also underwent the metal chloride-promoted addition of 1 at the carbonyl carbon or β-carbon. Georg Thieme Verlag Stuttgart.
- Miura, Katsukiyo,Nakagawa, Takahiro,Hosomi, Akira
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p. 1917 - 1921
(2007/10/03)
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- Reformatsky reaction of α-chloroesters with carbonyl compounds with commercially available zinc
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The condensation of α-chloroesters with aliphatic as well as aromatic ketones with commercially available zinc without any external metal additives is described.
- Chavan, Subhash P.,Shivasankar,Sivappa
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p. 406 - 407
(2007/10/03)
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- High-intensity ultrasound-promoted reformatsky reactions
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Reformatsky reactions of a phenyl ketone, an α-bromoester, zinc dust, and a catalytic amount of iodine in dioxane under high-intensity ultrasound (HIU) irradiation from an ultrasonic probe give high yields of β-hydroxyesters in short reaction times. A ser
- Ross, Nathan A.,Bartsch, Richard A.
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p. 360 - 366
(2007/10/03)
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- Microwave-promoted synthesis of β-hydroxyesters by the Reformatsky reaction in the absence of solvent
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A microwave-promoted Reformatsky reaction of aldehydes and ketones with ethyl bromoacetate, in the absence of solvent, using activated zinc metal and solid NH4Cl afforded the corresponding β-hydroxyesters in good to excellent yields.
- Gholap, Atul R.,Chavan, Abhijit P.
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p. 374 - 376
(2007/10/03)
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- A new method for the catalytic aldol reaction to ketones
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A new method for the catalytic aldol reaction to ketones, using CuF·3PPh3·2EtOH complex as the catalyst and (EtO)3SiF as the additive, is described. The reaction can be applied to a wide range of ketones and trimethylsilyl enolates. On the basis of mechanistic studies, a working hypothesis for the catalytic cycle is proposed, in which the dynamic ligand exchange mediated by copper silicates produces the active copper enolate. Moreover, the present reaction can be extended to the catalytic enantioselective reaction using tol-BINAP as a chiral ligand. Copyright
- Oisaki, Kounosuke,Suto, Yutaka,Kanai, Motomu,Shibasaki, Masakatsu
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p. 5644 - 5645
(2007/10/03)
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- Lithium Benzenetellurolate-induced Reformatsky-type Reaction in the Presence of Cerium Trichloride
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Reformatsky-type reactions with PhTeLi in the presence of CeCl3 proceeded smoothly under mild conditions.The PhTeLi-CeCl3 reagent was particularly efficient for the reactions of sterically hindered and enolizable ketones; in the absence of CeCl3 unsatisfactory yields of the desired β-hydroxy ketone were obtained.It is assumed that CeCl3 reactions involve a cerium enolate intermediate.The stereoselectivity of the reaction between ethyl 2-bromopropionate and benzaldehyde is also described.
- Fukuzawa, Shin-ichi,Hirai, Katsuhiko
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p. 1963 - 1966
(2007/10/02)
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- Mevalonic acid analogs as inhibitors of cholesterol biosynthesis
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A series of 20 mevalonic acid analogs were synthesized and tested for their ability to inhibit cholesterol biosynthesis from [2-14C]-mevalonate in rat liver homogenates. Removal of the 5-hydroxyl group from mevalonic acid produced an active inhibitor, 3-hydroxy-3-methylpentanoic acid. Removal of the 3-hydroxyl group, addition of an aromatic group in the 3-position, or insertion of a double bond reduced inhibitory activity. Compounds with an aromatic group or halide on the 5-position were active inhibitors. The most active inhibitor was 5-phenylpentanoic acid, with 50% inhibition at 0.064 mM.
- DeBold,Elwood
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p. 1007 - 1010
(2007/10/02)
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