Ethers and Related Compounds

Chromium complexes with crown ethers as ligands 90MI43. Cryptands as lipophilic cell ligands 86PAC1503. 

Design of cation selectivity of crown ethers as carriers in liquid membrane systems 86PAC1453. 

Electrochemistry of crown compounds in nonaqueous media 90MI40. Formation of free inorganic, organic and organometallic ions via their Li-salts, treatment with 12-crown-4 88ACR147. 

Lipophilic crown compounds as selective extracting agents 88ZC1. Metal ion selective color reactions with crown ether dyes 88-YGK96. 

Polymer-supported crown ethers, cryptands, and polyethylene glycols in organic synthesis 87MI43. 

Crown ethers with fluctuating ring size (a supply of activation energy 20 kcal moE suffices to vary the ring size reversibly), which have been called breathing crown ethers , have been synthesized which incorporate bullvalene into the ring. For bullvalene with two equal substituents, twelve positional isomers, i.e. four each of the 1,2-, 1,3-, and 1,4-isomers, can be formulated, so that for (55 n = 1) and (55 n = 2) the ring size varies between eleven and thirteen members, and between twenty and twenty-two members, respectively. 

Bottino, S. Foti, S. Pappalardo, and N. Bresciani-Pahor, Tetrahedron Lett., 1979, 1171. 

---

Both stereoselectivity and regioselectivity occur in the reaction of steroid vinyl esters, ethers, and related compounds with A -fluoropyridinium salts [75, 7d] (equation 45). 

In this chapter we discuss host-guest complexes of arenediazonium salts with crown ethers and related compounds. Transition metal complexes of arenediazonium ions are treated together with those of dinitrogen and of diazoalkanes in our second book (Zollinger, 1995, Sec. 10.1). 

The 1987 Nobel Prize in Chemistry was awarded to Charles J. Pedersen, Donald J. Cram, and Jean-Marie Lehn for their work on crown ethers and related compounds (host-guest chemisty). 

The efficient isomerization of allyl ethers and related compounds was accomplished by using NaHFe(CO)4 as catalyst. Isomerization of a homoallyl ether was also carried out in high yield (Scheme 32).56... 

Table 5. Oxidation potentials of silyl-substituted ethers and related compounds Compound Ep (V vs. Ag/AgCl) Compound Ep (V vs. Ag/AgCl)...

Silyl enol ethers are powerful intermediates in organic synthesis. Reactions of silyl enol ethers with various electrophiles provide effective methods for the synthesis of various carbonyl compounds. In this section we will briefly touch on the electrochemical reactions of silyl enol ethers and related compounds. The electrochemical behaviour of silyl enol ethers is expected to be closely related to that of allylsilanes and benzylsilanes because silyl enol ethers also have a silyl group ft to the re-system. 

Langer SH, Connell S, Wender I (1958) Preparation and properties of trimethylsilyl ethers and related compounds. J Org Chem 23 50-58... 

The first four chapters, which come under the general theme of sugar derivatives, represent methods for the transformation of sugar molecules into synthetically useful derivatives, such as acetals, dithioacetals, ethers, and related compounds. The following six chapters explore selected reactions of sugar derivatives, in which some of the most important bond-forming reactions in the modifications of sugars are discussed. 

Coumarin 7-Hydroxycoumarin 6-Hydroxycouma.rin 6,7-Dihydroxycoumarin Cyclic Enol Ethers and Related Compounds [419, 420]... 

TABLE 8. Oxidation potentials (/(,) of silylated ethers and related compounds... 

For Pd-catalyzed cross-coupling reactions the organopalladium complex is generated from an organic electrophile RX and a Pd(0) complex in the presence of a carbon nucleophile. Not only organic halides but also sulfonium salts [38], iodonium salts [39], diazonium salts [40], or thiol esters (to yield acylpalladium complexes) [41] can be used as electrophiles. With allylic electrophiles (allyl halides, esters, or carbonates, or strained allylic ethers and related compounds) Pd-i73-jt-allyl complexes are formed these react as soft, electrophilic allylating reagents. 

The photochemistry of ethers and related compounds (e.g. epoxides, acetals and hemi-acetals) is still relatively an unexplored field. Although activity in this field has increased recently, further work remains to be done and synthetic exploitation is still open to investigation. 

Crown ethers, azacrown ethers, and related compounds, thermodynamic and kinetic data on their interaction with cations and anions 91CRV1721. 

Treatment of (205) with a large excess of potassium t-butoxide in THF leads to ethers and related compounds their formation may be rationalised in terms of the formation of a cyclopropene (206) which can undergo a complex set of rearrangements to naphthylcarbenes which are then trapped by alkoxide ion l41, l43). 

In order to study the hydrogenolysis in phenyl ether and its relationship to the formation of intermediates, Fukuchi and Nishimura hydrogenated phenyl ether and related compounds over unsupported ruthenium, rhodium, osmium, iridium, and platinum metals in f-butyl alcohol at 50°C and the atmospheric hydrogen pressure.151 The results are shown in Tables 11.11 and 11.12. In general, the greater part of the initial products as determined by an extrapolation method has been found to be cyclohexyl phenyl ether, phenol, and cyclohexane (Table 11.11). Over ruthenium, however, cyclohexanol was found in a greater amount than phenol even in the initial products. Small amounts of cyclohexyl ether, 1-cyclohexenyl cyclohexyl ether, cyclohexanol, cyclohexanone, and benzene were also formed simultaneously. 

Review Unit 7 Alcohols, Ethers, and Related Compounds... 

This subject was covered previously in pages 993-1022 in CHEC-II(1996) (volume 9, chapter 36). This chapter is intended to update the previous work on major preparative and structural aspects of various types of rings containing silicon to lead that have been reported since 1995. As compared to previous work, two novel topics are covered reactivity and transformations of heterocyclic rings in Section 14.19.4 and application of computational methods in Section 14.19.5. Moreover, silacrown ethers and related compounds such as calixarenes, cyclophanes, and metallacenes are covered in Section 14.19.3.6. 

Enamines, enol ethers and related compounds again encompass one-site nucleophiles and two-site dipolarophiles. Where the adducts are acyclic or where a coelectrophile is involved these appear to be examples of equation (1). In equations (217)-(219), the paths to the major products seem straightforward. While a competing... 

Molecular Mechanics Treatment of Halogenated Dibenzo-f>-dioxins and Dibenzofurans MM2 Parameters for Aromatic Halides, Divinyl Ethers, and Related Compounds. ... 

FIGURE 7.11 Examples of reactions with silylenol ethers and related compounds. 

Library searching of mass spectral data from water and soil samples from U.S. hazardous waste sites taken between late 1987 and mid-1989 identified 2-butoxyethanol in 110 samples (Eckel et al. 1996). The total number of samples examined was not stated, and the study authors indicate that these data represent minimiun occurrences. Although the medium in which the compoimd was found was not indicated, the properties of 2-butoxyethanol led the study authors to suggest that it was most likely to have been found in water. Among the glycol ethers and related compounds for which the study authors searched, 2-butoxyethanol was found most frequently. Ethylene glycol mono acetate and tripropylene glycol monoethyl ether, were the second and third most frequently identified chemicals. 

Table 1.26 Bond dissociation energies of trifluoromethyl ethers and related compounds (CF3—X)a...

---