5259-65-4Relevant academic research and scientific papers
11-Step Total Synthesis of Pallambins C and D
Martinez, Luisruben P.,Umemiya, Shigenobu,Wengryniuk, Sarah E.,Baran, Phil S.
supporting information, p. 7536 - 7539 (2016/07/06)
The structurally intriguing terpenes pallambins C and D have been assembled in only 11 steps from a cheap commodity chemical: furfuryl alcohol. This synthesis, which features a redox-economic approach free of protecting-group manipulations, assembles all four-ring systems via a sequential cyclization strategy. Of these four-ring constructing operations, two are classical (Robinson annulation and Mukaiyama aldol) and two are newly devised. During the course of this work a method for the difunctionalization of enol ethers was developed, and the scope of this transformation was explored.
Synthesis of cyclohexadienylstannanes - Novel example of vinylic SRN1 mechanism: A theoretical and experimental study
Dorn, Viviana B.,Badajoz, Mercedes A.,Lockhart, María T.,Chopa, Alicia B.,Pierini, Adriana B.
, p. 2458 - 2462 (2008/09/20)
The reaction of trimethyltinsodium (1) with 1-(diethoxyphosphoryl)oxy-1,3-cyclohexadienes in liquid ammonia under irradiation affords the corresponding 1-trimethylstannylcyclohexadienes. We suggest that these reactions occur by an SRN1 mechanism. On the other hand, 2-(diethoxyphosphoryl)oxy-1,3-cyclohexadiene reacts very slowly towards 1 and the substitution product decomposes under the reaction conditions employed. Thus, structurally similar compounds do not behave in the same way under ET conditions. We suggest that this behavior is mainly due to differences in spin density of their radical anions, which affect their fragmentation rates. Our results are supported by computational calculations.
Synthesis of 4-hydroxy-4-methylcyclohex-2-en-1-one
Parladar, Vesile,Gueltekin, M. Serdar,Celik, Murat
, p. 10 - 11 (2007/10/03)
4-Hydroxy-4-methylcyclohex-2-en-1-one was synthesised from 4-methylanisole. The key step is the regioselective reaction of singlet oxygen with 4-methylcyclohex-3-en-1-one.
α-Acetyl- and α-Cyanovinyl 2,4-Dinitrophenyl Carboxylate as Useful Ketene Equivalents for the Diels-Alder Reaction
MaGee, David I.,Lee, May Ling
, p. 786 - 788 (2007/10/03)
Two ketene equivalents (5 and 35) have been developed for use in the Diels-Alder reaction. These dienophiles exhibit a marked increase in reactivity in comparison with the more conventional acetoxyacrylonitrile. Conversions of the cycloadducts to the requisite ketones occurs under mild, and moderate to high yielding conditions.
HIV PROTEASE INHIBITORS
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, (2008/06/13)
Peptide mimics, having a constrained peptide backbone conformation, are HIV protease inhibitors. A compound of this invention is, for example, 3-Benzyl-5(alaninyl-1-aminoethyl)-2,3,6,7-tetrahydro-N-azepinyl-2-propionyl-valinyl-valinyl methyl ester.
Reaction of Azoalkanes with Isolable Cation Radical Salts
Engel, Paul S.,Robertson, Donald M.,Scholz, John N.,Shine, Henry J.
, p. 6178 - 6187 (2007/10/02)
Three tertiary azoalkanes related in the sense acyclic, cyclic, and bicyclic are shown to evolve nitrogen upon oxidation with stable cation radical salts.Thus azo-tert-octane (ATO), 3,3,6,6-tetramethyl-1,2-diazacyclohexene (TMDAC), and 1,4-dimethyl-2,3-diazabicyclooct-2-ene (Me2DBO) react rapidly with thianthrenium perchlorate (Th(.1+)ClO4(1-)), tris(p-bromophenyl)aminium hexachloroantimonate (TBPA(.1+)SbCl6(1-)), and TBPA(.1+)SbF6(1-).The ether and olefin products, which are formed in high yield in CH2Cl2/MeOH solvent, are not those expected from the usual free-radical decomposition of azoalkanes but instead implicate carbocations.Althrough the reaction stoichiometry clearly requires 2 equiv of cation radical salt to one of azoalkane, the mechanism is not yet clearly defined.A complication in these studies is found in the ability of certain cation radical salts to oxidize more azoalkane than expected based on the 2:1 stoichiometry.
66. β-Cleavage of Potassium bicyclooct-5-en-2-olates. Stereoselective Synthesis of (+-)-Trichodiene
Snowden, Roger L.,Brauchli, Robert,Sonnay, Philippe
, p. 570 - 593 (2007/10/02)
The transformation of 12 bicyclooct-5-en-2-ols (V or VI) to 3-(cyclohex-3-enyl)-2-alkanones (III or IV), via β-cleavage of their potassium alkoxides in HMPA, has been investigated (cf. table I).As an illustration of this synthetic methodology, a stereoselective synthesis of (+)-trichodiene ((+)-1) is described wich involves the β-cleavage of the tricyclic potassium alkoxides 46a and 47a to cyclopentanone 4 (cf.Scheme 7).
DIENOPHILIE DES OLEFINES CAPTODATIVES-VII: CYCLOADDITIONS DE DIELS-ALDER DE L'α-METHYLTHIO-ACRYLATE DE METHYLE, REACTIONS THERMIQUES, REACTIONS CATALYSEES PAR UN ACIDE DE LEWIS ET TRANSFORMATIONS DES ADDUITS
Boucher, Jean-Luc,Stella, Lucien
, p. 3607 - 3616 (2007/10/02)
The Diels-Alder reactions of the α-methylthio methyl acrylate with simple dienes are investigated.The uncatalyzed thermal reactions proceed in high yield.With cyclic dienes they give adducts in wich the carbonyl containing substituent of the major product occupied the exo position.We have shown that with cyclopentadiene the stereoselectivity decreases with increasing temperature.In the presence of a Lewis acid catalyst, the regioselectivity is enhanced and the stereoselectivity is radically reversed.The cycloadducts are amenable to further usefull transformations which illustrate that the α-methylthio methyl acrylate can be used as a synthetic equivalent of either ketene or methoxycarbonyl-acetylene.
A Modified Route to 4-Methyl-3-cyclohexenone
Bhushan, Vidya,Rajopadhye, M. M.,Chandrasekaran, S
, p. 424 - 425 (2007/10/02)
4-Methyl-3-cyclohexenone (9) has been obtained pure starting from methoxyethoxymethyl ether (5) of p-cresol.Birch reduction of 5 furnishes 1-methoxyethoxymethoxy-4-methyl-1,4-cyclohexadiene (6), which undergoes cleavage with four equivalents of anhydrous zinc bromide under mild conditions to provide 9.
