A novel synthesis of 2'-hydroxy-1',3'-xylyl crown ethers

Leij, M. van der; Oosterink, H.J.; Hall, Richard H.; Reinhoudt, David N.

doi:10.1016/s0040-4020(01)98895-7

Cited by 21 publications

(6 citation statements)

References 24 publications

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“…Attempted reactions using other nucleophiles (Table , entries 10−13) either led to destruction of the ring system or no reaction. − McKervey et al found that oxocrown ethers are readily demethylated by LiI in what appears to be an example of catalysis by a crown ether . Reinhoudt et al report, however, that larger ring crown ethers fail to demethylate under these conditions. , When these conditions were applied to thiocrown ether 42 no reaction took place (Table , entry 14). Attempts to use cations other than lithium (Table , entries 15−17) were to no avail.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Enantiomerically Pure Thiocrown Ethers Derived from 1,1‘-Binaphthalene-2,2‘-diol

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Kellogg

1996

J. Org. Chem.

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Synthetic methodology is given for the preparation of two different types of thiocrown ethers from optically pure 1,1′-binaphthalene-2,2′-diol (10). The conceptually simplest approach starts from optically pure 10 itself, which is alkylated (4 equiv of K 2 CO 3 in DMF at 110°C) with 2-chloroethanol followed by mesylation to provide 2,2′-bis(2-(mesyloxy)ethoxy)-1,1′-binaphthyl (14). When allowed to react with ethane-1,2-dithiol, propane-1,3-dithiol, 1,4,7-trithiaheptane, 1,4,8,11-tetrathiaundecane, 2,2-dimethylpropane-1,3-dithiol, 2-(mercaptomethyl)-1-propene-3-thiol, and 1,2-benzenedithiol in the presence of Cs 2 CO 3 in DMF at 60°C the corresponding thiocrown ethers 22-25, 28, 30, and 32 are formed in 30-54% yields. Test reactions were carried out to establish that no racemization occurs during alkylation under these conditions. Reaction of optically pure 10 with tetrahydropyranyl (THP)-protected 3-chloropropanol under similar conditions for the preparation of 14 proceeded more sluggishly but cleanly. Removal of the THP protecting groups afforded 2,2′-bis-(3-bromopropoxy)-1,1′-binaphthyl (20), which on reaction with propane-1,3-dithiol, 1,5,9-trithianonane, 2,2-dimethylpropane-1,3-dithiol, 2-(mercaptomethyl)-1-propene-3-thiol, and 1,2-bis(mercaptomethyl)benzene provided the respective thiocrown ethers 26, 27, 29, 31, and 33 in 24-68% yields. Another class of thiocrown ethers was prepared from optically active 10, which was converted via ortholithiation to 3,3′-bis(bromomethyl)-2,2′-dimethoxy-1,1′-binaphthyl (39) by means of methylation (K 2-CO 3 /CH 3 I), ortho-lithiation followed by formylation (n-C 4 H 9 Li/N,N,N′,N′-tetramethylethylenediamine (TMEDA)/ether followed by DMF and H 2 O workup) followed by reduction (NaBH 4) followed by bromination (PBr 3 in C 5 H 5 N). Reaction (Cs 2 CO 3

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Section: Resultsmentioning

confidence: 99%

Synthesis of Enantiomerically Pure Thiocrown Ethers Derived from 1,1‘-Binaphthalene-2,2‘-diol

Stock

Kellogg

1996

J. Org. Chem.

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“…Cesium salts of organic acids often have good solubility in dipolar aprotic solvents . We had seen that the cesium salts of organic diacids and diphenols, formed by deprotonation with Cs 2 CO 3 , readily underwent cyclization reactions. , Reinhoudt et al demonstrated simultaneously that CsF induced the formation of crown ethers . The poor solubility characteristics of salts of 10 were overcome by use of Cs 2 CO 3 in dimethylformamide (DMF).…”

Section: Resultsmentioning

confidence: 99%

“…18,19 Reinhoudt et al demonstrated simultaneously that CsF induced the formation of crown ethers. 20 The poor solubility characteristics of salts of 10 were overcome by use of Cs 2 CO 3 in dimethylformamide (DMF).…”

Section: ■ Resultsmentioning

confidence: 99%

Practical Stereochemistry

Kellogg

2017

Acc. Chem. Res.

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The relationship between fundamental and applied is often uneasy, particularly in modern political climates. A familiar political view, aimed negatively at the scientific community, is that the former is a waste of money whereas the latter gives value for investment. The answer that fundamental is required as the basis for practical suffers from the fact that the timelines between fundamental and practical are often long and the routes contorted and unexpected. This has been my experience. In this Account, examples are given from the research in which I have been involved wherein quite fundamental considerations have led to various applications. The longer the time, the clearer and broader the relationship. Fundamental can and does lead to application. They need and depend on each other. I have seen this both from the side of academia and from small companies. In the course of the past 40 plus years, I have been involved in various aspects of stereochemistry and, in particular, chirality. It has been rewarding to see that several of the developments, most originally grounded in fundamental research considerations, have been used in the chemical community and given new dimensions and often practical applications by others. In this Account, a path-not planned deliberately by me-from orbital symmetry and Woodward-Hoffmann rules through crown ethers to conformational analysis to diastereomeric resolutions to deracemizations powered by Ostwald ripening and the Gibbs-Thomson effect to nucleation to helicenes is described. In order of discussion, the orbital symmetry aspects have via an unusual and unpredicted path has resulted in, among other things, a synthesis of hindered alkenes useful for the production of molecular motors. The crown ether aspects led to discovery of the utility of cesium salts particularly for racemization sensitive nucleophilic substitutions. Work on diastereomeric resolutions has concentrated on the mechanistic as well as practical/commercial aspects of the use of multiple resolving agents (Dutch resolution). During this work the complex relationship between nucleation and chirality in diastereomeric resolutions began to reveal itself. In general, nucleation, especially with involvement of chirality, is a topical challenge that has attracted the attention of many groups. The contribution of this knowledge to the development of attrition driven deracemizations of racemizable conglomerates is described. This remarkable technology allows, without intervention of chiral aids, conversion of certain racemates in quantitative yield and absolute enantiomeric excess to a single enantiomer. From a practical standpoint, this methodology has been used for the production in enantiomerically pure form of commercially interesting compounds like naproxen and clopidogrel (Plavix). Finally an STM investigation of the nucleation behavior of a helicene, prepared via a remarkably short and efficient route, on a metal surface is described.

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“…Methods for the protection of inward-facing phenolic groups in macrocyclic polyether compounds have recently received considerable attention. Methoxymethyl [ 11, methyl [2], ally1 [3], and acetyl [4] groups have been utilized for protection of phenolic functions during ringforming reactions. Subsequent deprotection has been accomplished under a variety of conditions.…”

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confidence: 99%