- An Efficient Route for γ-Alkyl-γ-butyrolactones
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An efficient route for γ-alkyl-γ-butyrolactones (1) involving iodolactonisation is described.
- Gurjar, M. K.,Purandare, A. V.
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p. 554 - 555
(2007/10/02)
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- A Simple, General Diastereoselective Synthesis of 5-Hydroxyalkylbutan-4-olides
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cis- and trans-Hex-4-enoic acids and their 6-n-propyl and n-butyl derivatives, when treated with a 1.1 molar excess of m-chloroperbenzoic acid and Amberlyst-15 as catalyst in CH2Cl2 at 20 deg C, gave the corresponding threo- and erythro-5-hydroxyalkylbutan-4-olides in quantitative yields.
- Jefford, Charles W.,Wang, Ying
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p. 1513 - 1514
(2007/10/02)
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- New Synthetic Methods, 12. - The Stereoselectivity of the Ramberg-Baecklund Rearrangement
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The influence of strong and weak bases in different solvents on the (E)/(Z) ratio of the Ramberg-Baecklund olefin synthesis of α-halosulfoncarboxylic acids in studied.With potassium tert-butoxide in dry dimethyl sulfoxide (E) ratios of more than 97 percent are achieved.With weak bases, such as 0.25 N sodium hydroxide, we found only equal amounts of (E) and (Z) olefins, apart from a few exceptions.
- Scholz, Dieter,Burtscher, Peter
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p. 517 - 521
(2007/10/02)
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- OXIDATION OF ALCOHOLS BY ELECTROCHEMICALLY REGENERATED NICKEL OXIDE HYDROXIDE. SELECTIVE OXIDATION OF HYDROXYSTEROIDS
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Primary alcohols, α,ω-diols and secondary alcohols are easily transformed into carboxylic acids, dicarboxylic acids or ketones, respectively, by heterogeneous oxidation with nickel oxide hydroxide electrochemically regenerated at a nickel hydroxyde electrode.The results are discussed in comparison to those of the nickel peroxide and chromic acid oxidation.The oxidation rate decreases with increasing steric hindrance of the alcohol, thus allowing the selective oxidation of the 3-position in hydroxysteroids.
- Kaulen, Johannes,Schaefer, Hans-J.
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p. 3299 - 3308
(2007/10/02)
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- Neue Synthesemethoden, 3. Tetrahydrothiopyran-3-on-1,1-dioxid, ein nuetzlicher 4-C-Baustein zur stereoselektiven Synthese von (Z)- oder (E)-γ,δ-ungesaettigten Carbonsaeuren
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By alkylation and ring opening together with bromination, tetrahydrothiopyran-3-one 1,1-dioxide (2) is converted into α-halosulfone intermediates, which can be transformed stereoselectively by Ramberg-Backlund rearrangement to (Z)- or (E)-γ,δ-unsaturated
- Scholz, Dieter
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p. 909 - 915
(2007/10/02)
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- Carbon-Carbon Bond Formation by the Use of Chloroiodomethane as a C1 Unit. II. The Preparation and Synthetic Application of 1-Chloro-3-iodoheptane
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Terminal alkenes, R-CH=CH2 (R=Et, n-Pr, n-Bu, N-Hex), were readily transformed into 1-chloro-3-iodoalkanes by the AIBN-induced free radical addition of chloroiodomethane.Thus, 1-chloro-3-iodoheptane was obtained from 1-hexene in an 88percent yield; this in turn was allowed to react with dialkyl malonates in the presence of alkoxides in alcohols to give dialkyl 2-butylcyclobutane-1,1-dicarboxylates and dialkyl (E)-3-octene-1,1-dicarboxylates (7), either of which could be obtained preferentially by the choice of the experimental parameters.The olefinic product, 7, was further utilized for the synthesis of (E)-5-decenyl acetate and/or 1,4-nonanolide.
- Miyano, Sotaro,Hokari, Hiroshi,Umeda, Yoshiharu,Hashimoto, Harukichi
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p. 770 - 774
(2007/10/02)
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- Action d'organolithiens et organomagnesiens sur la propiolactone en presence de sel cuivreux Synthese d'acides carboxyliques
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Organocuprate reagents, as well as Grignard reagents under the catalytic action of copper bromide, react with propiolactone to give the corresponding homologous acid with three more carbon atoms in good yields.
- Normant, J. F.,Alexakis, A.,Cahiez, G.
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p. 935 - 938
(2007/10/02)
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