52784-37-9Relevant academic research and scientific papers
Tandem Diels-Alder and retro-ene reactions of 1-sulfenyl- and 1-sulfonyl-1,3-dienes as a traceless route to cyclohexenes
Choi, Jin,Park, Hoyoon,Yoo, Hyun Jung,Kim, Sinae,Sorensen, Erik J.,Lee, Chulbom
, p. 9918 - 9921 (2014/08/05)
A pericyclic approach for the synthesis of six-membered ring structures is described. The method employs 1,3-dienes with a 1-sulfur substituent in a tandem sequence of Diels-Alder and retro-ene reactions. In this pairing of [4 + 2] cycloaddition and 1,5-sigmatropic rearrangement, 1-sulfenyl-1,3-dienes engage in Diels-Alder reactions with electron-deficient dienophiles. Subsequently, the sulfenyl group of the cycloadducts is oxidized and unmasked to form allylic sulfinic acids, which undergo sterospecific reductive transposition via sulfur dioxide extrusion. The sequence can also include an inverse electron demand Diels-Alder reaction by using a 1-sulfonyl-1,3-diene. This combination of two pericyclic events offers novel stereocontrolled access to cyclohexenes that are inaccessible via a direct [4 + 2] cycloaddition route.
Reactivity and stereoselectivity of the Diels-Alder reaction using cyclic dienophiles and siloxyaminobutadienes
Ohfusa, Toshiyuki,Nishida, Atsushi
experimental part, p. 1893 - 1906 (2011/04/17)
Several bicyclic compounds were synthesized by the Diels-Alder reaction using aminodiene and a cyclic dienophile. The stereochemistries of the obtained adducts were determined by X-ray crystallography or NMR analysis. The stereoselectivity of this Diels-A
Catalytic enantioselective Hosomi-Sakurai conjugate allylation of cyclic unsaturated ketoesters
Shizuka, Manami,Snapper, Marc L.
supporting information; experimental part, p. 5049 - 5051 (2009/03/11)
(Chemical Equation Presented) No fancy catalyst required: The copper-catalyzed enantioselective conjugate allylation of activated cyclic enones affords products in up to >98% ee. Reactions proceed to high conversion in the presence of commercially availab
Novel Routes to Chiral 2-Alkoxy-5-/6-methoxycarbonylmethylidenepyrrolidines/-piperidines
David, Olivier,Calvet, Sandrine,Chau, Francois,Vanucci-Bacque, Corinne,Fargeau-Bellassoued, Marie-Claude,Lhommet, Gerard
, p. 2888 - 2891 (2007/10/03)
We report the results of a study aimed at the diastereoselective synthesis of chiral 2-alkoxy-5-/6-methoxy carbonylmethylidenepyrrolidines/-piperidines by condensation of chiral amines onto ω-oxo alkynoates and ω-oxo β-keto esters.
Palladium(II)-catalyzed oxidation of aldehydes and ketones. 1. Carbonylation of ketones with carbon monoxide catalyzed by palladium(II) chloride in methanol
Hamed,El-Qisairi,Henry
, p. 180 - 185 (2007/10/03)
Unsubstituted or alkyl-substituted cyclic ketones react with PdCl2 in methanol under a CO atmosphere to give mainly acyclic diesters along with some acyclic chloro-substituted monoesters. The monosubstituted cyclic ketones, 2-hydroxy- and 2-methoxycyclohexanone, do not give ring cleavage but rather produce 2-(carbomethoxy)cyclohex-2-en-1-one. 13CO labeling experiments indicate one CO is inserted in forming the diester product so the second ester group must arise from the original ketone group. Two mechanisms are possible for the diester reaction. One involves initial Pd(II)-CO2CH3 insertion across the double bond of the enol form of the ketone while the second involves initial addition of Pd(II)-OCH3 followed by CO insertion into the new Pd(II) carbon bond formed. Pd(II) elimination and acid-catalyzed ring cleavage produce the second methyl ester group in both routes. The chloro-substituted monoester is formed by initial Pd(II)-Cl insertion across the double bond followed by the acid-catalyzed ring cleavage. The 2-(carbomethoxy)cyclohex-2-en-1-one must result from elimination of water or methanol from the α-ketoester product formed by the initial methoxycarbonylation of the enol form of the ketone. As expected, the acyclic ketone 2-decanone, formed methyl acetate and a mixture of methyl nonanoate and products.
SYNTHESES DE CYCLOHEXENONES α-SUBSTITUEES VIA LA THERMOLYSE DE CETOSULFOXYDES TERTIAIRES
Barillier, Daniel,Benhida, Rachid,Vazeux, Michel
, p. 83 - 96 (2007/10/02)
The sulfenylation-dehydrosulfenylation method, combined with carbon-carbon bond forming reactions, has been applied to the synthesis of some α-functionalized cyclohexenones 3.Hence, the sodium anion of the 2-methylthiocyclohexanone in THF reacts with primary, allyl and benzyl halides as well as with Michael acceptors to lead to the tertiary ketosulfides 1a-j.Further oxidation by NaIO4 and thermolysis in boiling toluene of the resulting sulfoxides 2 have been performed.The scope and limitations of this strategy are also discussed. Key Words: α-functionalized cyclohexenones; tertiary ketosulfides and ketosulfoxides; sulfenylation and deshydrosulfenylation; thermolysis.
AN ECONOMICAL DIELS-ALDER STRATEGY FOR THE SYNTHESIS OF DAPHNIPHYLLUM ALKALOIDS
Orban, John,Turner, John V.
, p. 2697 - 2700 (2007/10/02)
A convergent and essentially self-consistent strategy, featuring an unusual Diels-Alder reaction has been devised for the stereo-controlled synthesis of a logical tetracyclic precursor 21 to daphniphyllum alkaloids.
A Simple Method for the Efficient Synthesis of Unsaturated β-Dicarbonyl Compounds
Liotta, Dennis,Barnum, Christopher,Puleo, Robert,Zima, George,Bayer, Charlene,Kezar, Hollis S.
, p. 2920 - 2923 (2007/10/02)
β-Dicarbonyl compounds which are substantially enolized can be readily converted to their corresponding unsaturated derivative by (a) selenation using a 1:1 complex of phenylselenenyl chloride/pyridine and (b) in situ oxidation with 30percent H2O2 (after removal of the pyridine).The isolated yields of unsaturated β-dicarbonyl compounds obtained in this way are typically between 80percent and 100percent.If the selenation step (step a) is carried out in the presence of excess reagent, a slow ''nonoxidative'' elimination occurs.Synthetic and mechanistic details of this ''nonoxidative''process are discussed.
