The framework of altertoxin III, a mycotoxin produced by Alternaria fungi investing food and feed, has been synthesised for the first time. Synthetic schemes including Diels-Alder reactions of anthracene derivatives turned out to be not successful due to an aromatisation of key intermediates. This aromatisation was further investigated by DFT calculations, which showed that the aromatisation tendency is dependant from the electronic characteristics of attached substituents. A Friedel-Crafts-type hafnium triflate-catalysed dimerisation of dihydroxytetralins with subsequent benzylic oxidation furnished the target compound, which should be a suitable precursor for the synthesis of altertoxin III and related natural products. (C) 2013 Elsevier Ltd. All rights reserved.
"Hydrophobic" binding of water-soluble guests by high-symmetry, chiral hosts. An electron-rich receptor site with a general affinity for quaternary ammonium compounds and electron-deficient .pi. systems
Design and synthesis of a new class of hydrophobic binding sites
作者:Michael A. Petti、Timothy J. Shepodd、Dennis A. Dougherty
DOI:10.1016/s0040-4039(00)84106-4
日期:1986.1
The design, synthesis and basic aggregation and binding behavior of a new class of water-soluble molecules with hydrophobicbindingsites are reported.
报道了具有疏水性结合位点的新型水溶性分子的设计,合成,基本聚集和结合行为。
"Hydrophobic" binding of water-soluble guests by high-symmetry, chiral hosts. An electron-rich receptor site with a general affinity for quaternary ammonium compounds and electron-deficient .pi. systems
作者:Michael A. Petti、Timothy J. Shepodd、Richard E. Barrans、Dennis A. Dougherty
DOI:10.1021/ja00228a036
日期:1988.9
Evidence for the Importance of Polarizability in Biomimetic Catalysis Involving Cyclophane Receptors
作者:Sarah M. Ngola、Dennis A. Dougherty
DOI:10.1021/jo960521y
日期:1996.1.1
Cyclophanes 1-6 catalyze the nucleophilic dealkylation of a simple sulfonium compound by potassium iodide. The cation-pi interaction is important in substrate binding, but the primarily electrostatic nature of this effect does not explain all observations concerning catalysis. As a series of substituents are placed on the cyclophane framework, a systematic variation in catalyst effectiveness is seen, such that more polarizable substituents produce more potent catalysts. This provides support for the notion that transition states are especially polarizable, and catalysis can be enhanced by maximizing London dispersion forces. The reactions studied here are very similar to the broad class of biological methylations mediated by S-adenosylmethionine, and the biological catalysts may use forces similar to those described here.
An improved, two step synthesis of the chiral templating reagent 2,6-Dihydroxy-9,10-dihydro-11,12-dicarbomethoxyethenoanthracene
作者:James C. Adrian、Tina M. Ovitt
DOI:10.1016/0957-4166(96)00298-4
日期:1996.8
An improved, two step synthesis, of the importrant chiral templating reagent 2,6-Dihydroxy-9, 10-dihydro-11,12-dicarbomethoxyethenoanthracene 3 has been developed with an overall yield of 82% (not optimized). The reaction features a simple diastereomeric separation to afford the enantiomeric products. The reaction can be scaled up to afford multigram quantities of the ethenoanthracenes. Copyright (C) 1996 Elsevier Science Ltd
Changing the size of a cavity via an electron-transfer: synthesis and reduction of 1,5,22,26-tetraoxa-[5,5]-(2,8)-dibenzo[a,e]cylooctatetraenophane