- Total synthesis of the novel antifungal agent (±)-jesterone
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A total synthesis of the novel, biologically active epoxyquinone natural product (±)-jesterone has been accomplished from the readily accessible Diels-Alder adduct of cyclopentadiene and prenylated-p-benzoquinone. The approach delineated here is notable f
- Mehta, Goverdhan,Pan, Subhas Chandra
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- Enantioselective Halo-oxy- and Halo-azacyclizations Induced by Chiral Amidophosphate Catalysts and Halo-Lewis Acids
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Catalytic enantioselective halocyclization of 2-alkenylphenols and enamides have been achieved through the use of chiral amidophosphate catalysts and halo-Lewis acids. Density functional theory calculations suggested that the Lewis basicity of the catalyst played an important role in the reactivity and enantioselectivity. The resulting chiral halogenated chromans can be transformed to α-Tocopherol, α-Tocotrienol, Daedalin A and Englitazone in short steps. Furthermore, a halogenated product with an unsaturated side chain may provide polycyclic adducts under radical cyclization conditions.
- Lu, Yanhui,Nakatsuji, Hidefumi,Okumura, Yukimasa,Yao, Lu,Ishihara, Kazuaki
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supporting information
p. 6039 - 6043
(2018/05/14)
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- Highly Selective Synthesis of Ortho-Prenylated Phenols and Chromans by using a New Bimetallic CuAl-KIT-5 with a 3D-Cage-type Mesoporous Structure
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A nice piece of KIT: The first synthesis of a new bimetallic 3D-cage-type mesoporous catalyst CuAl-KIT-5 and its remarkable performance for the highly selective synthesis of ortho-prenylated phenols and chromans is reported.
- Varghese, Shaji,Anand, Chokkalingam,Dhawale, Dattatray,Mane, Gurudas P.,Wahab, Mohammad A.,Mano, Ajayan,Raj, George Allen Gnana,Nagarajan, Samuthira,Vinu, Ajayan
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p. 899 - 902
(2013/05/08)
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- Gold-catalyzed intramolecular hydroarylation of olefins. Scope evaluation and preliminary mechanistic studies
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We report a gold-catalyzed intramolecular hydroarylation of unactivated olefins using a combination of AuCl3/AgOTf as the catalytic system affording dihydrobenzopyrans, tetralins and tetrahydroquinolines in good yields. For our preliminary mechanistic studies, we have investigated the kinetic isotope effects with deuterated arene compounds and found that this catalytic hydroarylation is consistent with an electrophilic aromatic substitution process.
- Jean, Mickael,Van De Weghe, Pierre
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p. 3509 - 3513
(2011/07/09)
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- Regioselective iron-catalyzed decarboxylative allylic etherification
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[Chemical Equation Presented] An anionic iron complex catalyzes the decarboxylative allylation of phenols to form allylic ethers in high yield. The allylation is regioselective rather than regiospecific. This suggests that the allylation proceeds through π-allyl iron intermediates in contrast to related allylations of carbon nucleophiles that have been proposed to proceed via π-allyl complexes. Ultimately, iron catalysts have the potential to replace more expensive palladium catalysts that are typically utilized for decarboxylative couplings.
- Trivedi, Rushi,Tunge, Jon A.
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scheme or table
p. 5650 - 5652
(2010/02/28)
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- Alternative Lewis acids to effect Claisen rearrangement
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Yb(OTf)3 and DIBAL-H are developed as alternative Lewis acids for effecting Claisen rearrangement of allyl, crotyl and prenyl aryl ethers.
- Sharma,Ilangovan,Sreenivas, Punna,Mahalingam
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p. 615 - 618
(2007/10/03)
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- Reaction between phenols and isoprene under zeolite catalysis. Highly selective synthesis of chromans and o-isopentenylphenols
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Chromans 3 and o-isopentenylphenols 4 are synthesized in satisfactory to good yields and selectivities by the reaction of phenols and isoprene in the presence of the commercially available acid faujasite zeolite HSZ-360.
- Bigi, Franca,Carloni, Silvia,Maggi, Raimondo,Muchetti, Chiara,Rastelli, Massimo,Sartori, Giovanni
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p. 301 - 304
(2007/10/03)
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- Total synthesis of polyprenylhydroquinols and benzoquinones
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The total synthesis of polyprenylhydroquinols and benzoquinones is described.First, two appropriate aromatic allyl carbonates (moieties with one and two prenyls) and two activated bifunctional terpenyl derivatives (moieties with two and three prenyls) were synthesized.These molecules were then reacted together using a highly regio- and stereoselective coupling with Pd(PPh3)4 as a catalyst.The synthesis was achieved by functional group elimination and formation of quinonic and hydroquinonic moieties. - Keywords: polyprenylbenzoquinol; polyprenylhydroquinone; allylcarbonate; ?-allyl palladium complex
- Bouzbouz, Samir,Kirschleger, Bernard,Villieras, Jean
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- CHROMENES AND CHROMANONES. PART II. THE BIRCH REDUCTION OF PRECOCENE I AND PRECOCENE II
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The reduction of precocene I (1a), precocene II (1c) and 6-methoxy-2,2-dimethyl-2H-chromene (1b) with sodium or lithium in liquid ammonia was examined.The phenolic compounds and the bicyclic one with partialy reduced benzene ring were obtained as the majo
- Aniol, Miroslaw,Wawrzenczyk, Czeslaw
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p. 2655 - 2662
(2007/10/02)
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- Total synthesis of 2-tetraprenylbenzoquinol and -benzoquinone
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The total synthesis of 2-tetraprenylbenzoquinol and -benzoquinone is described. A key step in this synthesis is the highly regio- and stereoselective coupling between an appropriate aromatic allylcarbonate and an activated bifunctional farnesyl derivative
- Bouzbouz,Kirschleger
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p. 714 - 718
(2007/10/02)
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- The chemistry of Lactarius fuliginosus and Lactarius picinus
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Intact fruit-bodies of the Basidiomycetes Lactarius fuliginosus and L. picinus have been found to contain the stearic acid ester 4b. When the mushrooms are injured 4b is rapidly converted to the acrid free phenol 4a which is then gradually oxidized to a m
- De Bernardi,Vidari,Vita Finzi,Fronza
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p. 7331 - 7344
(2007/10/02)
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- Clay catalyzed rearrangement of substituted allyl phenyl ethers: Synthesis of ortho-allyl phenols, chromans and coumarans
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Montmorillonite clays catalyze the rearrangement of substituted allyl phenyl ethers to provide ortho-allyl phenols, chromans and coumarans under mild conditions.
- Dauben, William G.,Cogen, Jeffrey M.,Behar, Victor
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p. 3241 - 3244
(2007/10/02)
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- REGIOSPECIFIC ALKENYLATION OF PHENOLS BY ISOPRENE PROMOTED BY Pt(II) AND Pd(II) COMPLEXES
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Catalytic alkenylation of phenols with isoprene is promoted by Pd(II) or Pt(II) complexes.Ortho-isopentenylphenols are obtained together with the corresponding 2,2-dimethylchromans.The catalytic activity of the two d8 ions is compared.A possible mechanism is discussed.
- Felice, Vincenzo De,Renzi, Augusto De,Funicello, Maria,Panunzi, Achille,Saporito, Antonio
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- REGIOSPECIFIC ALKENYLATION OF PHENOLS BY 1,1-DIMETHYLALLENE PROMOTED BY PLATINUM CATALYSTS
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1,1-Dimethylallene reacts with phenolic substrates in the presence of catalytic amounts of platinum(II) complexes.A regiospecific C-alkenylation takes place, affording o-isopentenylphenols and 2,2-dimethylchromans.Possible reaction mechanisms are also discussed.
- Renzi, Augusto De,Panunzi, Achille,Saporito, Antonio,Vitagliano, Aldo
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p. 993 - 996
(2007/10/02)
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- Acid-catalysed Intramolecular Cyclization of Geranyl Hydroquinone Derivatives from Cordia alliodora. X-Ray Crystal and Molecular Structure of 1,2,3,3a,4,9,10,10a-Octahydro-5,8-dimethoxy-3,10-dimethyl-3a,9-epoxybenzazulene
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The aqueous acid-catalysed intramolecular cyclization of dimethylated alliodorin (2) obtained from the heartwood of Cordia alliodora has been characterized by X-ray analysis as the unusual tetracyclic di-O-methyl hydroquinone title compound (8).A new synthesis of di-O-methylalliodorin (2) from a terminal methylallylic sulphide derivative of 2-geranil-1,4-dimethoxybenzene is described. Crystals of the title compound (8) are monoclinic, space group P21/c, unit cell dimensions a = 14.984(7), b = 5.206(4), c = 20.131(9) Angstroem, β = 99.77(1) deg, Z = 4.The structure was solved by direct methods and refined by least-squares calculations to an R value of 0.078 for 1 832 independent reflections measured on a diffractometer using Cu-Kα radiation.
- Manners, Gary D.,Wong, Rosalind Y.
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p. 1849 - 1854
(2007/10/02)
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