- Synthesis of β-Methyl Alcohols: Influence of Alkyl Chain Length on Diastereoselectivity and New Attractants of Rhynchophorus ferrugineus
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The diastereoselectivity of adducts in the addition reaction via the Felkin-Anh model is affected significantly by the steric effect of bulky groups. However, the influence of steric alkyl chain length has not been studied for the diastereoselectivity. In this work, we present a new strategy for the racemic synthesis of β-methyl alcohols to obtain various diastereomer ratios using the Felkin-Anh model. The addition of alkyl Grignard reagents to α-methyl aldehydes afforded diastereomer ratios of threo/erythro ≈ 2:1, while the reduction in structurally related ketones using LiAlH4 afforded ratios of threo/erythro ≈ 1:1. The experimental data showed no effect of alkyl chain length on either side on the stereoselectivity of adducts. All synthesized analogues were evaluated for attractiveness to Rhynchophorus ferrugineus weevils in the field. Five novel derivatives, including two alcohols and three ketones, were found to attract weevils in the field trials. Among them, 3-methyldecan-4-one (5b) and 4-methyldecan-5-ol (11a) were found to be the most attractive to the insects.
- Le, Van-Dung,Dang, Chi-Hien,Nguyen, Cong-Hao,Nguyen, Hong-Ung,Nguyen, Thanh-Danh
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p. 5882 - 5886
(2021/06/21)
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- METHOD FOR PRODUCING BIO ALCOHOL FROM INTERMEDIATE PRODUCTS OF ANAEROBIC DIGESTION TANK
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The present invention relates to a method for producing a bio-alcohol by reacting a mixture of volatile fatty acid with methanol in 2 through 11 in a reactor in the presence of a 280 °C-membered alkaline earth metal catalyst or 400 °C transition metal catalyst formed based on a support.
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Paragraph 0043-0048
(2021/05/25)
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- Enantioselective preparation of the stereoisomers of 4-methylheptan-3-ol using Candida antarctica lipase B
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The four stereoisomers of 4-methylheptan-3-ol were prepared through fractional crystallization of a mixture of their racemic 4-methylhept-3-yl 3,5-dinitrobenzoates, followed by hydrolysis of each crystalline racemate and enantioselective, lipase-mediated transesterification of each pair of enantiomeric alcohols liberated, using the Candida antarctica lipase B as catalyst and 5-ethyl octanethioate as the acyl donor. An analytical method of determining the enantiomeric composition of mixtures of 4-methyl-heptan-3-ols was developed. The optical purity of the separated isomers was in the range of 29-97%.
- Unelius, C. Rikard,Sandell, Johan,Orrenius, Christian
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p. 525 - 533
(2007/10/03)
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- PREPARATION DES METHYL-4 HEPTANOLS-3 ERYTHRO ET THREO OPTIQUEMENT PURS.
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Optically pure enantiomers of threo and erythro 4-methylheptan-3 ols are synthesized from optically active butenolides 2 and 3 obtained via an asymmetric synthesis of propargylic carbinols.
- Vigneron, J. P.,Meric, R.,Dhaenens, M.
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p. 2057 - 2060
(2007/10/02)
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- Stereochemistry of Aliphatic Carbocations, 13. Protonated Cyclopropanes as Intermediates in 1,2-Alkyl Shifts
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The nitrous acid deamination of 2-ethyl-1-methylbutylamine (10), 1,2-diethylbutylamine (35), and 2-ethyl-1-methylpentylamine (43) has been studied with respect to 1,2-alkyl shifts.Optically active and deuterated amines were employed whenever possible.The structure, configuration, and deuterium distribution of various products (e. g. 16 from 10, 40 and 48 from 35, 56 from 43) are most reasonably explained in terms of alkyl-bridged intermediates (corner-protonated cyclopropanes) which isomerize via proton shifts from corner to corner.The alternative interconversion of open ions via 1,3-H shifts is incompatible with our experimental results.
- Kirmse, Wolfgang,Loosen, Karin,Prolingheuer, Ernst-Christoph
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p. 129 - 141
(2007/10/02)
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