- Enantioselective Construction of Modular and Asymmetric Baskets
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The precise positioning of functional groups about the inner space of abiotic hosts is a challenging task and of interest for developing more effective receptors and catalysts akin to those found in nature. To address it, we herein report a synthetic methodology for preparing basket-like cavitands comprised of three different aromatics as side arms with orthogonal esters at the rim for further functionalization. First, enantioenriched A (borochloronorbornene), B (iodobromonorbornene), and C (boronorbornene) building blocks were obtained by stereoselective syntheses. Second, consecutive A-to-B and then AB-to-C Suzuki–Miyaura (SM) couplings were optimized to give enantioenriched ABC cavitand as the principal product. The robust synthetic protocol allowed us to prepare (a) an enantioenriched basket with three benzene sides and each holding either tBu, Et, or Me esters, (b) both enantiomers of a so-called “spiral staircase” basket with benzene, naphthalene, and anthracene groups surrounding the inner space, and (c) a photo-responsive basket bearing one anthracene and two benzene arms.
- Badji?, Jovica D.,Finnegan, Tyler J.,Gunther, Michael J.,Pavlovi?, Radoslav Z.,Wang, Xiuze
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supporting information
p. 25075 - 25081
(2021/10/25)
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- Synthesis and [4 + 2] cycloaddition of (2R,2′R)-N, N′fumaroylbis[fenchane-8,2-sultam] (=(2E)-1,4-bis[(3aS,6S,7aR)-1,4,5,6,7, 7a-hexahydro-7,7-dimethyl-2,2-dioxido-3H-3a,6-methano-2,1-benzothiazol-1-yl] but-2-ene-1,4-dione) to cyclopentadiene
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The now corrected X-ray structure of (2R)-bornane-10,2-sultam ((-)-1a), as well as that of its already published N-crotonoyl derivative (-)-1d, were compared with those of the newly synthesized (2R)-fenchane-8,2-sultam ((+)-5a), as well as its N-crotonoyl
- Piatek, Anna M.,Chojnacka, Agnieszka,Chapuis, Christian,Jurczak, Janusz
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p. 2441 - 2453
(2007/10/03)
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- The first enantioselective synthesis of chiral norbornane-type 1,4-diamine ligand
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The asymmetric synthesis of trans-2,3-bis(aminomethyl)norbornane was performed starting with endo-2,3-norbornene dicarboxylate anhydride. Desymmetrization of meso-anhydride 1 and following selective epimerization gave the trans-monoester (+)-3 with a high enantiomeric excess (98% e.e.). LiAlH4 reduction of the trans-monoester to the 1,4-diol, which was then treated with phthalimide under Mitsunobu conditions and, following a Gabriel type amine synthesis with hydrazine hydrate, yielded a saturated and unsaturated diamine mixture. Hydrogenation of mixture finally afforded saturated diamine (+)-8 with a yield of 37%.
- Tanyeli, Cihangir,Oezcubukcu, Salih
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p. 1167 - 1170
(2007/10/03)
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- Stereoselectivity in the cycloaddition of cyclopentadiene to N-fumaroyl-[2R,S(R)]-bornane-10,2-sulfinamide monomethyl ester
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The cyclic [2R,S(R)]-bornane-10,2-sulfinamide (-)-2b, an analogue of Oppolzer's camphor-derived sultam (-)-2a, was synthesized by reduction of the known N-alkylidenesulfinamide (+)-1b with NaBH4. The uncatalyzed [4 + 2] cycloaddition of cyclopentadiene to the methyl ester (-)-3b of the N-fumaroylsulfinamide, obtained from (-)-2b, proceeds with lower endo and π-facial selectivity as compared to dienophiles (-)-3a, c. In contrast to these latter, the diastereoselectivity is reversed either in apolar CCl4 or in the presence of TiCl4. This inversion is explained by a competitive C(α)-si addition on the reactive anti-s-trans conformer.
- Chapuis, Christian,Kawecki, Robert,Urbanczyk-Lipkowska, Zofia
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p. 579 - 588
(2007/10/03)
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- Stereoselectivity in the TiCl4-catalyzed [4 + 2] cycloaddition of cyclopentadiene to (2R)-bornane-10,2-sultam derivatives of fumaric acid monoesters
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The [4 + 2] cycloaddition of cyclopentadiene to the (2R)-bornane-10,2- sultam derivative (-)-1b of fumaric monomethyl ester proceeds with high endo and π-facial diastereoselectivity in the presence of 0.5 mol-equiv. of TiCl4. The major diastere
- Achmatowicz, Michal,Chapuis, Christian,Rzepecki, Piotr,Jurczak, Janusz
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p. 182 - 190
(2007/10/03)
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- 12. Complete ?-Facial Stereoselectivity in the TiCl4-Mediated Cycloaddition of Cyclopentadiene to N,N-Fumaroyldi
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Under the co-operative influence of two prosthetic groups, and independent of the TiCl4 concentration, complete and constant diastereofacial ?-selection was achieved during the cycloaddition of cyclopentadiene to N,N'-fumaroyl-di((-)-1c); reactive conformations are discussed.
- Chapuis, Christian,Rzepecki, Piotr,Bauer, Tomasz,Jurczak, Janusz
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p. 145 - 150
(2007/10/02)
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- THERMAL AND CATALYTIC DIELS-ALDER REACTIONS BETWEEN (2E)-4,5,6-TRI-O-ACETYL-2,3-DIDEOXY-ALDEHYDO-D-ERYTHRO-HEX-2-ENOSE AND CYCLOPENTADIENE
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Thermal and catalytic reactions between (2E)-4,5,6-tri-2,3-dideoxy-aldehydo-D-erythro-hex-2-enose (1) and cyclopentadiene 1ed, in each case, to the four stereoisomeric 5-formyl-6-(1,2,3-tri-O-acetyl-D-erythro-triol-1-yl)bicyclohept-2-enes (2-5).The role of the catalysts is discussed, and the face selectivity is rationalized in terms of both steric and electrostatic arguments.Upon subsequent sodium borohydride reduction, iodination, and zinc reduction, the adducts 2-5 were converted to their respective primary alcohols 6-9, that could be separated by column chromatography.Sequential basic deacetylation, oxidative cleavage of the sugar side-chain with sodium metaperiodate, and reduction with sodium borohydride, yielded the previously known (5R,6R)- or(5S,6S)-bis(hydroxymethyl)norbornene-diols 12 or 13, thus establishing the C-5 and C-6 absolute configurations of their synthetic precursors.
- Serrano, Jose A.,Garcia, Eulalia G.,Roman, Emilio
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p. 1121 - 1134
(2007/10/02)
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- 1-Mesityl-2,2,2-trifluoroethanol, an outstanding new chiral controller for catalyzed diels-alder reactions
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The R2AlCl-catalyzed Diels-Alder reactions of cyclopentadiene with the (R)-1-mesityl-2,2,2-trifluoroethyl esters of acrylic and fumaric acid proceed with ? 97:3 diastereoselectivity.
- Corey,Cheng, Xue-Min,Cimprich, Karlene A.
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p. 6839 - 6842
(2007/10/02)
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- Enzymatic resolution of norbor(NE)nylmethanols in organic media and an application to the synthesis of (+)- and (-)-endo-norbornene lactone
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The enzymatic resolution of some norbornene carboxylic acids, norbornenylmethanols and -methylamines was evaluated. The kinetic resolution of norbornyl- and norbornenylmethanols by Porcine Pancreatic Lipase (PPL)-catalyzed transesterification in methyl acetate as the solvent leads to corresponding acetates and remaining methanols both of high enantiomeric purity. A useful application is the synthesis of both enantiomers of endo-norbornene lactone 8n via transesterification of iodolactone 18. The influence of structural variations on the efficiency of the PPL-catalyzed resolution of lactone methanols 21, 23, 25 and 28, at the optimal reaction conditions established for iodolactone 18, was investigated.
- Janssen,Klunder,Zwanenburg
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p. 5513 - 5538
(2007/10/02)
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- Asymmetric Diels-Alder Reaction with use of (S)-5-(Trityloxymethyl)pyrrolidin-2-one as a Chiral Auxiliary
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(S)-5-(Trityloxymethyl)pyrrolidin-2-one (1) is an efficient and recyclable chiral auxiliary in the asymmetric Diels-Alder reaction of the imide (2) with dienes, affording cycloadducts (3) with excellent diastereofacial selectivity.
- Tomioka, Kiyoshi,Hamada, Noriko,Suenaga, Toshiro,Koga, Kenji
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p. 426 - 428
(2007/10/02)
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- Enzymatic Preparation of Optically Active Bicycloheptene Derivatives, Building Blocks of Terpenoid Natural Products. An Attractive Alternative to Enantioselective Diels-Alder Syntheses
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Bicycloheptene derivatives (1)-(3), building blocks of terpenoid natural products, have been prepared with high enantiometric purities by enzymatic hydrolysis of their racemic esters in the presence of porcine liver esterase (PLE) and an ester hydrolase from Pseudomonas sp. (SAM-II).
- Eycken, J. Van der,Vandewalle, M.,Heinemann, G.,Laumen, K.,Schneider M. P.,et al.
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p. 306 - 308
(2007/10/02)
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- A Convenient Synthesis of Both Enantiomeric 2,3-Disubstituted 5-Norbornenes from D-Mannitol
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A convenient synthesis of both enantiomeric trans- and cis-2,3-disubstituted 5-norbornenes (bicycloheptenes), 2 and 3, has been developed by utilizing the Diels-Alder reaction between cyclopentadiene and chiral dienophiles obtained from a single chiral template D-mannitol (1).
- Takano, Seiichi,Kurotaki, Ayako,Ogasawara, Kunio
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p. 1075 - 1078
(2007/10/02)
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- Stereochemical Versatility in Synthesis of Substituted Cycloalkanes from Acyclic Unsaturated Sugars
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Acyclic unsaturated sugars obtained by Wittig extension of aldehydo arabinose precursors undergo stereoselective Diels-Alder addition of cyclopentadiene, permitting isolation of a single, crystalline, optically pure norbornene adduct whose stereochemistry may be controlled by the enantiomeric form of the sugar used and the conditions of the cycloaddition reaction.
- Horton, Derek,Machinami, Tomoya,Takagi, Yasushi,Bergmann, Carl W.,Christoph, Gary C.
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p. 1164 - 1166
(2007/10/02)
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- CHIRAL SYNTHESIS OF ASYMMETRICALLY TETRA-SUBSTITUTED CYCLOPENTANE DERIVATIVES BY DIELS-ALDER ADDITION OF CYCLOPENTADIENE TO UNSATURATED ACYCLIC-SUGAR DERIVATIVES
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Optically pure, substituted cyclopentane derivatives of interest in synthesis of prostaglandin analogs have been obtained by stereocontrolled addition of cyclopentadiene to trans α,β-unsaturated sugar derivatives.Methyl (E)-4,5,6,7-tetra-O-acetyl-2,3-dide
- Horton, Derek,Machinami, Tomoya,Takagi, Yasushi
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p. 135 - 162
(2007/10/02)
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