17042-16-9Relevant articles and documents
Gas-phase Unimolecular Chemistry of Ethyl Butyl Ketone Cations
Bouchoux, Guy,Flammang, Robert,Jaudon, Pascale,Lefevre, Odile
, p. 1189 - 1196 (1993)
Mass spectra of the four isomeric ethyl butyl ketones, C2H5CO-n-C4H9 (1), C2H5CO-iso-C4H9 (2), C2H5CO-sec-C4H9 (3) and C2H5CO-t-C4H9 (4), are reported.The structure of the fragment ions produced from precursors of both high and low internal energy were identified by collision experiments in a six-sector mass-spectrometer.Metastable molecular ions 1(+.) and 2(+.) behave identically in expelling CH3(.), C3H6 and C2H5(.) to produce the same fragment ions: (+), (+.) and a mixture of (+) and (+), respectively.The key isomerization step between 1(+.) and 2(+.) is a 1,2-enol-olefin shift.Metastable molecular ions 3(+.) and 4(+.) give essentially ethene and ethyl losses, respectively; the fragment ions are (+.) and (+).Keto-enol isomerization also occurs to a significant extent for ions 1(+.) and 2(+.) and 3(+.).In contrast, 1,2- or 1,3-ethylhydroxycarbene migrations are only marginal processes.
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Gough,T.E. et al.
, p. 2529 - 2535 (1967)
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Synthesis of β-Methyl Alcohols: Influence of Alkyl Chain Length on Diastereoselectivity and New Attractants of Rhynchophorus ferrugineus
Le, Van-Dung,Dang, Chi-Hien,Nguyen, Cong-Hao,Nguyen, Hong-Ung,Nguyen, Thanh-Danh
, p. 5882 - 5886 (2021/06/21)
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.
Investigating: Saccharomyces cerevisiae alkene reductase OYE 3 by substrate profiling, X-ray crystallography and computational methods
Powell, Robert W.,Buteler, M. Pilar,Lenka, Sunidhi,Crotti, Michele,Santangelo, Sara,Burg, Matthew J.,Bruner, Steven,Brenna, Elisabetta,Roitberg, Adrian E.,Stewart, Jon D.
, p. 5003 - 5016 (2018/10/17)
Saccharomyces cerevisiae OYE 3 shares 80% sequence identity with the well-studied Saccharomyces pastorianus OYE 1; however, wild-type OYE 3 shows different stereoselectivities toward some alkene substrates. Site-saturation mutagenesis of Trp 116 in OYE 3 followed by substrate profiling showed that the mutations had relatively little effect, opposite to that observed previously for OYE 1. The X-ray crystal structures of unliganded and phenol-bound OYE 3 were solved to 1.8 and 1.9 ? resolution, respectively. Both structures were nearly identical to that of OYE 1, with only a single amino acid difference in the active site region (Ser 296 versus Phe 296, part of loop 6). Despite their essentially identical static X-ray structures, molecular dynamics (MD) simulations revealed that loop 6 conformations differed significantly in solution between OYE 3 and OYE 1. In OYE 3, loop 6 remained nearly as open as observed in the crystal structure; by contrast, loop 6 closed over the active site of OYE 1 by ca. 4 ?. Loop closure likely generates a greater number of active site protein contacts for substrate bound to OYE 1 as compared to OYE 3. These differences provide an explanation for the differing stereoselectivities of OYE 3 and OYE 1, despite their nearly identical X-ray crystal structures.
α-alkylation of ketones by addition of zinc enamides to unactivated olefins
Nakamura, Masaharu,Hatakeyama, Takuji,Nakamura, Eiichi
, p. 11820 - 11825 (2007/10/03)
A zinc enamide generated from the corresponding N-aryl imine undergoes addition to an unactivated olefin, such as ethylene, 1-octene, and isobutylene, to generate an α-alkylated γ-zincioimine intermediate in good to excellent yield. Terminal and gem-disubstituted olefins react with >99% regioselectivity, allowing the C-C bond formation to take place at the more hindered carbon of the double bond. The organozinc intermediate undergoes further C-C bond formation with a carbon electrophile to give, upon hydrolysis of the imine, an α-alkylated ketone bearing a variety of functionalized primary, secondary, and tertiary alkyl groups.
