- Synthesis of a biofuel target through conventional organic chemistry
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In this work, the biofuel target compound 2-ethyl-5,5-dimethylcyclopenta-1,3-diene (1) and its exo isomers (9a and 9b), were successfully synthesized via two different pathways from the common intermediate 4,4-dimethylcyclopent-2-ene-1-one (2). The first pathway produced the endocyclic product as a pure isomer via a triflate intermediate obtained from ketone 2 in 60% yield, followed by copper-catalyzed coupling with ethyl magnesium bromide in 63% yield. The second pathway employed a Grignard reaction with ketone 2, which generated an alcohol that was immediately subjected to mild acid-catalyzed elimination to yield primarily a mixture of exo isomers 9a and 9b in 46% yield. The preparation method developed by this work allowed for the production of a sufficient quantity of these targets to evaluate their fuel properties, which will be reported in a separate study.
- Page, Jordan P.,Robinson, Joshua W.,Albrecht, Karl O.,Cosimbescu, Lelia
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supporting information
p. 1421 - 1423
(2018/03/07)
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- Synthesis and Neurotrophic Activity Studies of Illicium Sesquiterpene Natural Product Analogues
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Neurotrophic natural products hold potential as privileged structures for the development of therapeutic agents against neurodegeneration. However, only a few studies have been conducted to investigate a common pharmacophoric motif and structure–activity relationships (SARs). Here, an investigation of structurally more simple analogues of neurotrophic sesquiterpenes of the illicium family is presented. A concise synthetic route enables preparation of the carbon framework of (±)-Merrilactone A and (±)-Anislactone A/B on a gram scale. This has allowed access to a series of structural analogues by modification of the core structure, including variation of oxidation levels and alteration of functional groups. In total, 15 derivatives of the natural products have been synthesized and tested for their neurite outgrowth activities. Our studies indicate that the promising biological activity can be retained by structurally simpler natural product analogues, which are accessible by a straightforward synthetic route.
- Richers, Johannes,P?thig, Alexander,Herdtweck, Eberhardt,Sippel, Claudia,Hausch, Felix,Tiefenbacher, Konrad
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supporting information
p. 3178 - 3183
(2017/03/13)
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- Concise total syntheses of the bioactive mesotricyclic diterpenoids jatrophatrione and citlalitrione
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The highly functionalized [5.9.5] tricyclic framework resident in jatrophatrione (1) and citlalitrione (2) has been synthesized. The route begins with the tandem anionic oxy-Cope rearrangement/methylation/transannular ene cyclization of 21 and subsequent introduction of a conjugated enone double bond. Hydroxyl-directed 1,4-reduction of this functionality in 25 with LiAlH4/Cul/hexamethylphosphoramide/tetrahydrofuran sets the stage for the implementation of a Grob fragmentation and expedited generation of 27. Stereocontrolled intramolecular hydrosilylation allows for the subsequent introduction of a cyclic carbonate as in 53. This intermediate undergoes remarkably efficient, fully regiocontrolled Treibs reaction to generate 54, with this maneuver serving as a pivotal step for making 1 available five steps later. Treatment of 1 with m-chloroperbenzoic acid leads to 2, with attack occurring preferentially on a α-face of the double bond more remote to the carbonyl.
- Yang, Jiong,Long, Yun Oliver,Paquette, Leo A.
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p. 1567 - 1574
(2007/10/03)
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- A simple strategy for spirocyclopentannulation of cyclic ketones. Formal total synthesis of (±)-acorone
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A general and simple methodology for spirocyclopentannulation of cyclic ketones (or 4,4-disubstituted cyclopentenones from acyclic ketones) and its application in the synthesis of the spirodienone 7 via a prochiral precursor constituting a formal total synthesis of (±)-acorone (6), are described.
- Srikrishna, Adusumilli,Kumar, P. Praveen,Viswajanani, Ranganathan
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p. 1683 - 1686
(2007/10/03)
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- EFFECTIVE CATALYTIC OXIDATION OF 1-ALKENES USING PALLADIUM-NITRO COMPLEXES IN THE PRESENCE OF AMIDES
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The rate of oxidation and the catalyst stability in the oxidation of 1-alkenes with O2 using as catalyst is considerably improved by the use of amides as ligands or solvents.
- Kiers, Niklaas H.,Feringa, Ben L.,Leeuwen, Piet W. N. M. van
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p. 2403 - 2406
(2007/10/02)
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- Synthesis and Chemistry of Azolenines. Part 16. Preparation of both 3H- and 2H-Pyrroles from 2,2-Disubstituted 1,4-Diketones via the Paal-Knorr Reaction, and Isolation of Intermediate 2-Hydroxy-3,4-dihydro-2H-pyrroles
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Treatment of 2,2-disubstituted 1,4-diketones (1) with liquid ammonia gives high yields of isolable isomeric 2-hydroxy-3,4-dihydro-2H-pyrroles (10) and (11), many of which may be dehydrated to 3H-pyrroles (2) together, in certain cases, with isomeric methylene-pyrrolines (14) and (15).When heated in acetic acid with ammonium acetate, the diketones (1) yield 2H-pyrroles (18), sometimes in admixture with 3H-pyrroles (2) from which they are formed by rearrangement.The diketones (1), including some novel examples, are prepared from nitro-ketones (6) by the Nef reaction, as well as other methods.
- Lui, Kon-Hung,Sammes, Michael P.
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p. 457 - 468
(2007/10/02)
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- 1,4-Ketoaldehydes via Michael-Addition of deprotonated Aldimines to 2-(N-Methylanilino)-acrylonitrile
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A new method for the synthesis of the title compounds by a one-pot three component coupling reaction is described.It consists of the reaction of an enolateanion- and an enolcation-equivalent with subsequent alkylation of an acylanion-equivalent.
- Ahlbrecht, Hubertus,Daacke, Axel von
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- Selective Reduction via Enolate Protection
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The use of enolate anions as protecting groups in order to effect the selective reduction of dicarbonyl compounds is studied.
- Kraus, George A.,Frazier, Kevin
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p. 4262 - 4263
(2007/10/02)
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