Synthesis of 8,16-dimethyl- and 8,16-dimethoxy-5,13-di-t-butyl[2.2]metacyclophane-1,2,9,10-tetraone

Tsukamoto, Ken ichi; Sahade, Daniel A.; Taniguchi, Masahiko; Sawada, Tsuyoshi; Thiemann, Thies; Mataka, Shuntarō

doi:10.1016/s0040-4039(99)00845-x

Cited by 4 publications

(4 citation statements)

References 13 publications

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“…A few years ago, we prepared the in -fluorosilane 2 by the direct condensation of trithiol and tribromide precursors,7c but a similar attempt to make an in -methylsilane gave only the out -isomer 3 7c. Until now, metacyclophane 4 has possessed the closest approach of a methyl carbon to the center of an aromatic ring (3.00 Å), , even though the C−Me bond vector does not even point toward the opposing ring! We now report the syntheses of in -methylcyclophanes 9 and 10 (Scheme ), in which the methyl groups are forced into the centers of the basal aromatic rings with interesting spectroscopic and structural consequences.…”

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confidence: 99%

Sterically Congested in-Methylcyclophanes

Song

Pascal

2005

J. Am. Chem. Soc.

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The crowded in-methylcyclophane 9 was prepared by condensation of 1,8,13-tris(bromomethyl)-9-methyltriptycene and 1,3,5-tris(mercaptomethyl)benzene under high dilution conditions. Oxidation of 9 gave the highly crystalline trisulfone 10, and its X-ray structure was determined. The in-methyl carbon atoms of the two independent molecules in the structure are only 2.90 and 2.87 A from the centroid of the basal aromatic ring, the closest such contacts ever observed. In addition, the C-CH3 bonds in these cyclophanes are compressed; the two independent bond distances are 1.475 and 1.495 A, significantly shorter than the ca. 1.54 A distances found in similar but uncongested molecules.

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confidence: 99%

Sterically Congested in-Methylcyclophanes

Song

Pascal

2005

J. Am. Chem. Soc.

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“…[50] Alternatively, the arms of 34 are long enough to allow it to distort so that the phosphane might react with electrophiles, but the results of such reactions were surprising. [54] This very unusual metacyclophane was prepared by further oxidation and fragmentation of an oxygenated 10b,10c-dimethyl-10b,10c-dihydropyrene, which had itself been generated by oxidative ring closure of a tetrahydroxy metacyclophane. [50] Sulfuration should not display this problem, but although triphenylphosphane itself reacts with sulfur in seconds at room temperature, the reaction of 34 requires high enough temperatures that phosphorus inversion (∆G ‡ ϭ 35 kcal/mol) and sulfuration lead to the out isomer 36!…”

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confidence: 99%

Molecular “Iron Maidens”: Ultrashort Nonbonded Contacts in Cyclophanes and Other Crowded Molecules

Pascal

2004

Eur J Org Chem

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Ultrashort nonbonded interactions involving aromatic rings should be the sole province of cyclophane chemists, but it is not always so. In this review, the structures, syntheses, and properties of molecules exhibiting the closest nonbonded contacts of various atoms and functional groups with the faces of aromatic rings are discussed and illustrated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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“…Bridged aromatic compounds, such as cyclophanes (CPs), are potential building blocks in the design of molecules for catalytic processes or electronic devices. The restricted conformational mobility of these compounds, their intrinsic symmetry, and their structural features, some of which are very exotic, addressed the attention on the development of a number of synthetic pathways . ThiaCPs 2 represent significant components of the CP family because the presence of sulfur atoms into the skeleton of the cage allows a number of possible transformations of the hetero function 3 and some interesting conformational changes …”

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confidence: 99%

Thiacyclophane Cages and Related Bi- and Tripodal Molecules via Transient Polysulfenic Acids

et al. 2007

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A series of bis- and tris-bridged thiacyclophane S-oxides, as racemates or meso products, have been synthesized with a new procedure. Starting from the corresponding thiols, in three steps, transient polyarene- and polyarylmethane-sulfenic acids were generated in the presence of di- and triethynylbenzenes. The thermal syn-addition of these sulfenic acids onto the triple bonds of the unsaturated acceptors was conducted in CH2Cl2 at 40 degrees C. The concentration of sulfoxide precursors of sulfenic acid and the sulfoxide/acceptor molar ratio addressed the syn-addition toward open-chain benzene sulfoxides or thiacyclophane S-oxides. Complete stereochemical control was observed in some reactions between polysulfenic acids and ethynylbenzenes, where the meso dithiacyclophane S,S'-dioxides were obtained exclusively, whereas 1:1 mixtures of meso/rac dithiacyclophanes S,S'-dioxides were isolated as products of other reactions. In almost all the cases, the obtained compounds were separated by column chromatography. The structure assignment of the new heterophanes was done on the basis of their diagnostic NMR spectra and X-ray crystallographic analysis of some of them. Open-chain polysulfinyl and polysulfinylmethyl benzenes, obtained as meso/rac mixtures, were separated and the products were fully characterized. Both synthesized cages, including trithia[3(3)](1,3,5)cyclophane S,S',S' '-trioxides, and bi- and tripodal benzene sulfoxides, appear promising in the field of coordination and material chemistry.

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Synthesis of 8,16-dimethyl- and 8,16-dimethoxy-5,13-di-t-butyl[2.2]metacyclophane-1,2,9,10-tetraone

Cited by 4 publications

References 13 publications

Sterically Congested in-Methylcyclophanes

Sterically Congested in-Methylcyclophanes

Molecular “Iron Maidens”: Ultrashort Nonbonded Contacts in Cyclophanes and Other Crowded Molecules

Thiacyclophane Cages and Related Bi- and Tripodal Molecules via Transient Polysulfenic Acids

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