6137-11-7Relevant academic research and scientific papers
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.
Formation, Alkylation, and Hydrolysis of Chiral Nonracemic N-Amino Cyclic Carbamate Hydrazones: An Approach to the Enantioselective α-Alkylation of Ketones
Huynh, Uyen,McDonald, Stacey L.,Lim, Daniel,Uddin, Md. Nasir,Wengryniuk, Sarah E.,Dey, Sumit,Coltart, Don M.
, p. 12951 - 12964 (2018/11/30)
The α-alkylation of ketones is a fundamental synthetic transformation. The development of asymmetric variants of this reaction is important given that numerous natural products, drugs, and related compounds exist as α-functionalized ketones or derivatives thereof. We previously reported our preliminary studies on the development of a new enantioselective ketone α-alkylation procedure using N-amino cyclic carbamate (ACC) auxiliaries. In comparison to other auxiliary-based methods, ACC alkylation offers a number of advantages and is both highly enantioselective and high yielding. Herein, we provide a full account of our studies on the enantioselective ACC ketone α-alkylation method.
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.
New Simple Polymeric Supports with Hydrazone Linkers for Solid-Phase Synthesis of Ketones and Primary Amines
Lazny, Ryszard,Nodzewska, Aneta,Wolosewicz, Karol
, p. 2858 - 2864 (2007/10/03)
The preparation of new solid supports with hydrazine anchoring groups and their application to solid-phase synthesis of ketones and primary amines are described. The supports were used for immobilization of ketones, 4-tert-butylcyclohexanone, pentan-3-one, acetone, N-methylpiperidone, N-benzylpiperidone, and tropinone in the form of their hydrazones. The polymer-supported hydrazones were subjected to deprotonation/alkylation procedure (LDA/RX) once or twice. The resulting alkylated products were cleaved off the solid support on treatment with trifluoroacetic acid in tetrahydrofuran providing α-alkylated or α,α′-bisalkylated ketones or were subjected to reductive cleavage with borane in tetrahydrofuran to give β-alkylated or β,β′-bisalkylated primary amines.
Application of piperazine-derived hydrazone linkers for alkylation of solid-phase immobilized ketones
Lazny, Ryszard,Michalak, Michal
, p. 1931 - 1934 (2007/10/03)
The preparation and application of three new solid supports with piperazine-derived hydrazine anchoring groups are described. The supports were used for immobilization of ketones. The ketones: cyclohexanone, 4-tert-butylcyclohexanone, 3-pentanone and tropinone, which were bound to polymers in the form of their hydrazones, were deprotonated with LDA and alkylated with propyl iodide or benzyl bromide. The resulting alkylated products were cleaved off the solid support on treatment with trifluoroacetic acid in dichloromethane. Linkers with 6- and 3-carbon atom spacers gave better results than the simple N-aminopiperazine linker.
Identification and assignment of the absolute configuration of biologically active methyl-branched ketones from limnephilid caddis flies
Bergmann, Jan,Loefstedt, Christer,Ivanov, Vladimir D.,Francke, Wittko
, p. 3175 - 3179 (2007/10/03)
Glands of the 4th and 5th abdominal stemite of the caddis flies Potamophylax latipennis, Potamophylax cingulatus, and Glyphotaelius pellucidus contain (S)-4-methyl-3-heptanone (4a), (4S,6S)-4,6-dimethyl-3-octanone (4b), and (4S,6S)-4,6-dimethyl-3-nonanone (4c). As shown by gas chromatography coupled with electrophysiological recordings, these ketones elicit a strong response in the insects' antennae. The structural assignment of the compounds was achieved on the basis of mass spectra, enantioselective synthesis, and gas chromatography on a chiral stationary phase.
Copper(II) chloride mediated racemization-free hydrolysis of α- alkylated ketone SAMP-hydrazones
Enders, Dieter,Hundertmark, Thomas,Lazny, Ryszard
, p. 27 - 33 (2007/10/03)
Treatment of ketone SAMP-hydrazones 1a-k with an aqueous copper(II) chloride solution yields the corresponding ketones 2a-k in 52-94% yield and with high enantiomeric purities (ee = 89-99%). The cleavage conditions do not affect functionalities sensitive to oxidation and strong acids. The alkylation/cleavage protocol can be carried out in 'one-pot'.
Reaction of α-Silyl Esters with Grignard Reagents: A Synthesis of β-Keto Silanes and Ketones. Preparation of the Douglas Fir Tussock Moth Pheromone
Larson, Gerald L.,Hernandez, David,Lopez-Cepero, Ingrid Montes de,Torres, Luz E.
, p. 5260 - 5267 (2007/10/02)
A variety of α-diphenylmethylsilyl esters have been prepared and reacted with Grignard reagents.The reaction is relatively slow in refluxing THF and can be controlled to allow the addition of 1 equiv of the Grignard reagent, providing the corresponding β-keto silane.Protiodesilylation of the β-keto silane results in the overall conversion of an ester to a ketone.This ester to ketone methodology has been applied to a two-step synthesis of the pheromone of the Douglas fir tussock moth.The β-keto silanes are viable precursors to regioselectively generated enol silyl ethers.The reaction of ethyl 2-methyl-2-(diphenylmethylsilyl)propionate with vinylmagnesium bromide or 2-methyl 1-propenylmagnesium bromide results in the addition of 2 equiv of the Grignard reagent, the second in a Michael fashion.
