154279-12-6Relevant articles and documents
Strained silacycle-catalyzed asymmetric Diels-Alder cycloadditions: the first highly enantioselective silicon Lewis acid catalyst
Kubota, Katsumi,Hamblett, Christopher L.,Wang, Xiaolun,Leighton, James L.
, p. 11397 - 11401 (2006)
The first highly enantioselective silicon Lewis acid catalyst for an asymmetric organic transformation has been developed. The catalyst derives its activity from the strain induced in the silicon center by virtue of being constrained in a five-membered ri
Endo/exo stereoselectivity in Diels-Alder reactions of α,β-Dialkylated conjugated enals to cyclic 1,3-dienes: Intermediates in the synthesis of (-)-β-santalol and its analogs
Chapuis, Christian,Skuy, David,De Saint Laumer, Jean-Yves,Brauchli, Robert
, p. 1470 - 1516 (2014)
Highly exo-selective [4+2] cycloadditions of cyclopenta-1,3-diene 2a to α,β-dialkyl conjugated enals 5 are compared with the analogous endo-favored Diels-Alder reaction of cyclohexa-1,3-diene 7. The exostereoselectivity is lower in the homologous case of methylcyclopenta-1,3-diene 9. This diastereoselectivity is discussed either in terms of a retro-homo-Diels-Alder reaction, associated with thermodynamic control, or with respect to either a competing hetero-Diels-Alder/Claisen or Cope domino pathway, or retro-Claisen/retro-hetero-Diels-Alder of the endo-homo-cycloadducts. These hypothetical mechanisms have been examined by DFT calculations at the MPW1K(CH2Cl2)/6-31+G? ? level of theory for the AlCl3-mediated cycloadditions of 5d to 2a and 7. Application of Corey's methodology to the g-halogenoa- methyl-substituted dienophiles 5a and 5b allowed an enantioselective preparation of known and useful intermediates for the synthesis of either the naturally occurring (-)-β-santalol or its potentially olfactive structural analogs.
Bis-selenonium Cations as Bidentate Chalcogen Bond Donors in Catalysis
He, Xinxin,Wang, Xinyan,Tse, Ying-Lung Steve,Ke, Zhihai,Yeung, Ying-Yeung
, p. 12632 - 12642 (2021/10/21)
Lewis acids are frequently employed in catalysis but they often suffer from high moisture sensitivity. In many reactions, catalysts are deactivated because of the problem that strong Lewis acids also bond to the products. In this research, hydrolytically stable bidentate Lewis acid catalysts derived from selenonium dicationic centers have been developed. The bis-selenonium catalysts are employed in the activation of imine and carbonyl groups in various transformations with good yields and selectivity. Lewis acidity of the bis-selenonium salts was found to be stronger than that of the monoselenonium systems, attributed to the synergistic effect of the two cationic selenonium centers. In addition, the bis-selenonium catalysts are not inhibited by strong bases or moisture.
Diazepane Carboxylates as Organocatalysts in the Diels–Alder Reaction of α-Substituted Enals
H?ggman, Nicklas O.,Zank, Benjamin,Jun, HyunJune,Kaldre, Dainis,Gleason, James L.
supporting information, p. 5412 - 5416 (2018/10/20)
Ethyl diazepane carboxylate efficiently catalyzes the Diels–Alder cycloaddition of α-substituted-α,β-unsaturated aldehydes via iminium ion organocatalysis. The reaction is applicable to a range of dienes and dienophiles and generally proceeds at room temperature in the presence of 5 mol-% catalyst and 2.5 mol-% triflic acid co-catalyst. The incorporation of a stereogenic center on the diazepane backbone in combination with a menthyl carbamate produces a catalyst which affords enantioselectivities of 70–95 % ee for the cycloaddition of cyclopentadiene with a range of dienophiles. The enantioselectivity is rationalized via a transition state in which electrostatic stabilization by the carboxylate directs the diene to the more hindered face of the dienophile.
Remote Tris(pentafluorophenyl)borane-Assisted Chiral Phosphoric Acid Catalysts for the Enantioselective Diels-Alder Reaction
Hatano, Manabu,Ishihara, Hideyuki,Goto, Yuta,Ishihara, Kazuaki
supporting information, p. 564 - 570 (2016/03/12)
Tris(pentafluorophenyl)borane-assisted chiral supramolecular phosphoric acid catalysts were developed for the model Diels-Alder reaction of α-substituted acroleins with cyclopentadiene. Two remotely coordinated tris(pentafluorophenyl)boranes should help to increase the Bronsted acidity of the active center in the supramolecular catalyst and create effective bulkiness for the chiral cavity. The prepared supramolecular catalysts acted as not only conjugated Bronsted acid-Bronsted base catalysts but also bifunctional Lewis acid-Bronsted base catalysts with the addition of a central achiral Lewis acid source such as catecholborane.
Enantioselective Diels-Alder Reaction Induced by Chiral Supramolecular Lewis Acid Catalysts Based on CN?B and PO?B Coordination Bonds
Hatano, Manabu,Hayashi, Kazushi,Sakamoto, Tatsuhiro,Makino, Yuma,Ishihara, Kazuaki
, p. 1061 - 1067 (2016/05/19)
Chiral supramolecular boron Lewis acid catalysts were prepared from chiral 3-phosphoryl-1,1′-bi-2-naphthols, (2-cyanophenyl)boronic acids, and tris(pentafluorophenyl)borane, bound through CN···B and PO···B coordination bonds. In particular, the coordinated tris(pentafluorophenyl)boranes increase the Lewis acidity of the active center in the manner of a Lewis acid assisted Lewis acid catalyst system. A possible cavity in these catalysts was highly suitable for several Diels-Alder probe reactions of acroleins with cyclic or acyclic dienes, which gave the corresponding adducts in good to high yields and high enantio-selectivities.
Catalytic enantioselective construction of all-carbon quaternary stereocenters by an organocatalytic Diels-Alder reaction of α-substituted α,β-unsaturated aldehydes
Kano, Taichi,Tanaka, Youhei,Osawa, Kenta,Yurino, Taiga,Maruoka, Keiji
supporting information; experimental part, p. 1956 - 1958 (2009/09/06)
A binaphthyl-based primary amine (R)-3d was designed for the Diels-Alder reaction of α-substituted α,β-unsaturated aldehydes; in the presence of the TfOH salt of (R)-3d, the Diels-Alder reaction of α-substituted α,β-unsaturated aldehydes with cyclopentadi
Asymmetric desymmetrization based on an intramolecular haloetherification: A highly effective and recyclable chiral nonracemic auxiliary, 2-exo-methyl-3-endo-phenyl-5-norbornene-2-carboxaldehyde, for meso-1,3- and meso-1,4-diols
Fujioka, Hiromichi,Fujita, Tetsuya,Kotoku, Naoyuki,Ohba, Yusuke,Nagatomi, Yasushi,Hiramatsu, Atsushi,Kita, Yasuyuki
, p. 5386 - 5397 (2007/10/03)
A new chiral auxiliary, a 3-endo-phenyl norbornene aldehyde derivative, which is a crystalline, very stable, and easily handled, was developed for the desymmetrization of meso-1,3- and meso-1,4-diols. The key step of the method, an intramolecular bromoeth
A new cationic, chiral catalyst for highly enantioselective Diels-Alder reactions
Sprott, Kevin T.,Corey
, p. 2465 - 2467 (2007/10/03)
(Matrix presented) The Diels-Alder reaction of cyclopentadiene and 2-methacrolein is catalyzed by a chiral Lewis acid to form the exo adduct in 96% yield and 96% ee.
