24108-29-0Relevant academic research and scientific papers
A Catalytic Asymmetric Ene Reaction for Direct Preparation of α-Hydroxy 1,4-Diketones as Intermediates in Natural Product Synthesis
Aitken, Harry R. M.,Brimble, Margaret A.,Furkert, Daniel P.
, p. 687 - 690 (2020)
Asymmetric access to α-hydroxy-1,4-diketones has been achieved by direct ene coupling of silyl enol ethers with glyoxal electrophiles, mediated by a chiral N, N ′-dioxide-nickel(II) complex catalyst. Successful union of a polyketide silyl enol ether with an α-quaternary glyoxal, generated by dioxirane oxidation of an α-diazo ketone, models a proposed C 5 -C 6 disconnection of the polyketide and spirocyclic imine domains of the marine natural product, portimine.
Organocatalytic enantioselective total synthesis of (-)-arboricine
Wanner, Martin J.,Boots, Rowan N.A.,Eradus, Bram,De Gelder, Rene,Van Maarseveen, Jan H.,Hiemstra, Henk
, p. 2579 - 2581 (2009)
The tetracyclic indole alkaloid (-)-arboricine has been prepared using an asymmetric organocatalytic Pictet - Spengler reaction as the key step followed by a diastereoselective Pd-catalyzed iodoalkene/enolate cyclization. The absolute stereochemistry was unequivocally proven by X-ray crystallographic analysis and appeared to be opposite to the published structure in the original paper.
(5 E/ Z,7 E,9)-Decatrien-2-ones, Pineapple-like Flavors from Fomitopsis betulina - Structure Elucidation and Sensorial Properties
Grosse, Miriam,Pendzialeck, Tim,Fohrer, Jorg,Berger, Ralf G.,Krings, Ulrich
, p. 10329 - 10335 (2019/12/30)
During the cultivation of the edible mushroom Fomitopsis betulina on agro-industrial side streams, a pleasant flavor strongly reminiscent of pineapple was perceived. Aroma extract dilution analyses identified two flavor components with a distinct pineapple odor. On the basis of mass spectrometric data, a Wittig reaction of (E)-penta-2,4-dien-1-yltriphosphonium bromide with ethyl levulinate was conducted. The resulting (5E/Z,7E,9)-decatrien-2-ones were identical to the compounds isolated from the fungal culture. Some structurally related methyl ketones were synthesized, confirmed by nuclear magnetic resonance and mass spectrometry, and their odor was characterized. The lowest odor threshold and most characteristic pineapple-like odor was found for (5Z,7E,9)-decatrien-2-one. Global minimum energy calculation of the methyl ketones and the comparison to (1,3E,5Z)-undecatriene, a character impact compound of fresh pineapple, showed that a chain length of at least 10 carbon atoms and a terminal double bond embedded in a "L"-shaped conformation were common to compounds imparting an intense pineapple-like odor. Both (5E/Z,7E,9)-decatrien-2-ones have not been described as natural flavor compounds.
Concise catalytic asymmetric total synthesis of biologically active tropane alkaloids
Cordova, Armando,Lin, Shuangzheng,Tseggai, Abrehet
supporting information; experimental part, p. 1363 - 1372 (2012/06/18)
A general strategy for the total asymmetric synthesis of valuable tropane alkaloids by catalytic stereoselective transformations is disclosed. The power of this approach is exemplified by the concise catalytic enantioselective total syntheses of (+)-methylecgonine, (-)-cocaine and (+)-cocaine as well as the first catalytic asymmetric total syntheses of a cocaine C-1 derivative and (+)-ferruginine starting from 5-oxo-protected-α,β-unsaturated enals using only two and three column chromatographic purification steps, respectively. Copyright
Enantioselective hydroformylation of N-vinyl carboxamides, allyl carbamates, and allyl ethers using chiral diazaphospholane ligands
McDonald, Richard I.,Wong, Gene W.,Neupane, Ram P.,Stahl, Shannon S.,Landis, Clark R.
supporting information; experimental part, p. 14027 - 14029 (2011/01/04)
Rhodium complexes of diazaphospholane ligands catalyze the asymmetric hydroformylation of N-vinyl carboxamides, allyl ethers, and allyl carbamates; products include 1,2- and 1,3-aminoaldehydes and 1,3-alkoxyaldehydes. Using glass pressure bottles, short reaction times (generally less than 6 h), and low catalyst loading (commonly 0.5 mol %), 20 substrates are successfully converted to chiral aldehydes with useful regioselectivity and high enantioselectivity (up to 99% ee). Chiral Roche aldehyde is obtained with 97% ee from the hydroformylation of allyl silyl ethers. Commonly difficult substrates such as 1,1- and 1,2-disubstituted alkenes undergo effective hydroformylation with 89-97% ee and complete conversion for six examples. Palladium-catalyzed aerobic oxidative amination of allyl benzyl ether followed by enantioselective hydroformylation yields the β3-aminoaldehyde with 74% ee.
Preparation of bicyclic 1,2,4-trioxanes from γ,δ-unsaturated ketones
Ramirez, Armando P.,Thomas, Andrew M.,Woerpel
supporting information; experimental part, p. 507 - 510 (2009/08/07)
(Chemical Equation Presented) Treatment of γ,δ-unsaturated ketones with hydrogen peroxide and acid provides a rapid entry into the medicinally important 1,2,4-trioxane structure. Alkene substitution that stabilizes carbocationic intermediates proved to be important for the success of this transformation.
Triquinanes from linear ketones via trimethylenemethane diyls
Lee, Hee-Yoon,Kim, Won-Yeob,Lee, Sejin
, p. 1407 - 1410 (2007/10/03)
Linear compounds containing a ketone and diene functional groups reacted with the anion of TMS-diazomethane to produce alkylidene carbenes that underwent intramolecular cyclopropanation followed by the formation of trimethylenemethane diyls which underwent [2+3] cycloaddition reaction to produce linearly fused triquinanes.
Facile entry to substituted decahydroquinoline alkaloids. Total synthesis of lepadins A-E and H
Pu, Xiaotao,Ma, Dawei
, p. 6562 - 6572 (2007/10/03)
Condensation of a L-alanine derived δ-bromo-β-silyloxy- propylamine with 1,3-cyclohexadione followed by alkylative cyclization produces a bicyclic enone. Diastereoselective Pt/C-catalyzed hydrogenation of this enone in HOAc provides a 5-oxo-cis-fused decahydroquinoline. Wittig olefination of this decahydroquinoline and subsequent epimerization of the resulting 5-formyl intermediate gives rise to a 5-β-formyl decahydroquinoline exclusively. In a parallel procedure, Peterson reaction of this decahydroquinoline and subsequent hydrogenation of the generated 5-exo-olefin provides a decahydroquinoline with a 5-α-substituent predominantly. For these two diastereoselective processes, using the intermediates without N-protection as the substrates is essential because the corresponding N-Boc intermediates give poor diastereoselectivity. The intermediate with β-form side chain is further converted into lepadins A-C via carbon chain elongation, while the intermediate with α-form side chain is transformed into lepadins D, E, and H and corresponding 5′-epimers via connection with two sulfones generated from two Sharpless epoxidation products. By comparison of the rotations and NMR data, the stereochemistry of lepadins D, E, and H is assigned as 2S,3R,4aS,5S,8aR,5′R.
The DDQ mediated cyclization products of some 2-hydroxy-3(1′-alkenyl)-1,4-naphthoquinones
Ameer, Farouk,Giles, Robin G.F.,Green, Ivan R.,Nagabhushana, Kyatanahalli S.
, p. 369 - 380 (2007/10/03)
The DDQ mediated cyclisation products derived from 2-hydroxy-3-(1′-alkenyl)-1,4-napthoquinones viz. 17 were found to be temperature dependent. At 60°C the naphthofuranquinone 19 was the predominant isomer whereas at 8°C the naphthopyranquinone 18 was exclusively formed.
Tandem hemiketal formation-intramolecular Friedel-Crafts alkylation: A facile route to hetero-atom-substituted benzo-fused bicyclo[3.3.1]nonanes
Wu, Yikang,Li, Yan,Wu, Yu-Lin
, p. 163 - 171 (2007/10/03)
A previously unknown intramolecular Friedel-Crafts alkylation with in situ formed hemiketals as the electrophile is reported.
