3883-56-5Relevant academic research and scientific papers
Thermal Isomerization of Isodicyclopentadiene and Its Cycloaddition Reactions
Subramanyam, Ravi,Batlett, Paul D.,Iglesias, Graciela Y. Moltrasio,Watson, William H.,Galloy, Jean
, p. 4491 - 4498 (1982)
Isodicyclopentadiene (4) undergoes a sigmatropic hydrogen shift at elevated temperatures (170-180 deg C) to form an isomeric, higly reactive diene intermediate 5 which readily undergoes cycloaddition reactions with dienophiles like dichlorovinylene carbonate (DCVC, 8), vinylene carbonate (VC, 7), and maleic anhydride (9).In all cases addition to 5 occurs exclusively from the exo face.While 7 and 8 under these high-temperature conditions give one major addition product each (12 and 13, respectively), in accord with Alder's rule, 9 at high temperature yields the two isomeric product 15 and 16 initially in the ratio 1:3 of which the isomer 16 (Alder's rule product) on prolonged heating is converted into the stable isomer 15 (anti Alder's rule product).The cycloaddition reactions of 4-cyclopentene-1,3-dione (10), 2,2-dimethyl-4-cyclopentene-1,3-dione (11), and dimethyl acetylenedicarboxylate (28) with 4 and 5 are also discussed.In situ formation of 5 at 0 deg C by photolytic cleavage of diketone 14 is proved by trapping 5 with maleic anhydride.X-ray crystallographic data are provided for the adducts 12, 13, 15, 16, and 21.
Photochemical Approaches to the Bilobalide Core
Emsermann, Jens,Opatz, Till
, p. 3362 - 3372 (2017)
Bilobalide is a tetracyclic sesquiterpene containing three contiguous γ-lactone rings and an unusual tert-butyl group, which is found in the leaves of the ginkgo tree (Ginkgo biloba). Three different photochemical approaches towards bilobalide's unique sk
Diastereoselective Synthesis of an Advanced Intermediate of Thapsigargin and Other 6,12-Guaianolides Using a RCEYM Strategy
Jouanneau, Morgan,Bonepally, Karunakar Reddy,Jeuken, Alan,Tap, Aurélien,Guillot, Régis,Ardisson, Janick,Férézou, Jean-Pierre,Prunet, Jo?lle
, p. 2176 - 2180 (2018)
A new and flexible approach toward the synthesis of 6,12-guaianolide anticancer drugs such as trilobolides or thapsigargin has been developed that could be applied to the preparation of analogues with a modified ring system. The synthesis starts from commercial 2-methylcyclopentane-1,3-dione, only relying on diastereoselective reactions for the construction of the stereogenic centers at C1, C3, C6, and C10 and features a high-yielding ring-closing enyne metathesis (RCEYM) step for the formation of the [5,7] bicyclic core.
Synthetic studies toward sordarin: Building blocks for the terpenoid core and for analogues thereof
Schule, Arnaud,Liang, Huan,Vors, Jean-Pierre,Ciufolini, Marco A.
supporting information; experimental part, p. 1587 - 1597 (2009/07/24)
Avenues to bi- and tricyclic building blocks for the elaboration of sordaricin and its analogues are described. The target molecules were obtained through inter- and intramolecular Diels-Alder reactions of a number of previously unknown cyclopentadienes. Unusual properties of 3-cyanoenones and 1-cyanocyclopen-tadienes have been unveiled and circumvented.
Mild acetalisation of mono and dicarbonyl compounds catalysed by titanium tetrachloride. Facile synthesis of β-keto enol ethers
Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
, p. 217 - 225 (2007/10/03)
The use of TiCl4, as a catalyst for the acetalisation, at room temperature, of carbonyl compounds is reported. Cyclic ketones and cyclic 1,4-diketones easily afford dimethyl acetals, but cyclic 1,3-diketones give β-keto enol ethers. Additionally, aryl ketones and acyclic ketones failed to react. β-keto aldehydes can be monoprotected either as β-keto enol ethers or β-keto dimethyl acetals depending on the reaction time and catalyst amount. Some mechanistic features are accounted for.
Moenomycin A: New chemistry that allows to attach the antibiotic to reporter groups, solid supports, and proteins
Kempin, Uwe,Hennig, Lothar,Knoll, Dietmar,Welzel, Peter,Mueller, Dietrich,Markus, Astrid,Van Heijenoort, Jean
, p. 17669 - 17690 (2007/10/03)
Moenomycin A (18) on reaction with the diazonium salt derived from bifunctional (protected) 15 yields the coupling product 19 which on reduction is converted into the moenomycin thiol derivative 21. Thiol 21 has been used to prepare selectively moenomycin dansyl and biotin adducts 26 and 28, respectively. This work was performed with the aim to use moenomycin as a tool for studies of the transglycosylation step in peptidoglycan biosynthesis.
Reaction of Phosphonate-Stabilized Carbanions with Cyclic Enones Bearing a β-Leaving Group
Mphahlele, Malose J.,Modro, Tomasz A.
, p. 8236 - 8240 (2007/10/03)
Reaction between α-lithiated alkylphosphonic esters and α,β-unsaturated cyclopentenones and cyclohexenones carrying a heteroatom substituent Y in the β-position was studied.Complete chemoselectivity was observed as a function of substituent Y.For Y = OMe exclusive addition-elimination at the β-carbon was observed, yielding α,β-unsaturated δ-ketophosphonates.The β-chloro-substituted substrates (Y = Cl) derived from cyclohexenone reacted exclusively at the carbonyl carbon, yielding (2-hydroxyalkyl)phosphonates with the retained chlorovinyl function.The alcohols, depending on the conditions, could be dehydrated to two different products.The reaction of 3-chlorocyclopent-2-en-1-one with diethyl (lithiomethyl)phosphonate occured at the β-carbon, but the ketophosphonate product was isolated in a stable enolic form.
A New Approach to Hydroazulenes via Olefin Metathesis
Junga, Heiko,Blechert, Siegfried
, p. 3731 - 3732 (2007/10/02)
Several functionalized diolefins cyclize to hydroazulenes (among others) via olefin metathesis with CH3ReO3.These conversions are regioselective and occur with high diastereoselectivity.
