With Replacement of Alkoxy Groups

Heating of tellurium tetrakis[fluoroalkoxides] with arenesulfonamides produced tellurium arenesulfonimide bis[fluoroalkoxides].  

Tellurium tetrakis[2,2,2-trifluoroethoxide] reacted with 1,4,7,10-tetraazacyclododecane (LH4) in tetrahydrofuran/pentane at — 20° to yield a cationic tellurium complex with two LH4 ligands, two tellurium atoms, and two bridging oxygen atoms. The compound, isolated as the chloride, crystallized with four molecules of chloroform and two molecules of methanol. 

The tellurium atom is in a pentagonal bipyramidal environment with three nitrogen atoms and two oxygen atoms in the equatorial plane. The nitrogen atom covalently bonded to the tellurium atom is in the apical position.  

Tellurium tetrakis[fluoroalkoxides] reacted with tellurium tetrahalides in benzene or tetrahydrofuran to yield fluoroalkoxy tellurium halides with one, two, or three flu-oroalkoxy groups in the molecule depending on the molar ratio of the reagents.  

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With Replacement of Alkoxy Groups and Rednction of Tellurium... 

The hydrolysis rate can be controlled by replacement of alkoxy group with the help of a chelating group. 

In addition to conversion to chloro compounds, -ones and diones have given thiones with phosphorus pentasulfide, whilst in some cases replacement by amine of alkoxy groups in preference to a chloro group has been observed (68JHC13). 

Triazole reacts with acetals in the presence of ppts in dioxane by alkylation at N(l) with replacement of one of the acetal alkoxy groups <90H(3i)2029>. The second acetal group can then be replaced by an amide (Scheme 5). 

So far, we have seen that an enolate anion is able to act as a nucleophile in an SN2 reaction (Sections 20.3 and 20.4) and also in an addition reaction to the carbonyl group of an aldehyde in the aldol condensation (Section 20.5). It also can act as a nucleophile in a substitution reaction with the carbonyl group of an ester as the electrophile. When an ester is treated with a base such as sodium ethoxide, the enolate ion that is produced can react with another molecule of the same ester. The product has the a-carbon of one ester molecule bonded to the carbonyl carbon of a second ester molecule, replacing the alkoxy group. Examples of this reaction, called the Claisen ester condensation, are provided by the following equations ... 

Soluble low-valent metal alkoxides can also be synthesized by replacing small alkoxy group OR by bulky polydentate ligands such as 2-methoxyethanol CH3OC2H4OH. This solvent is currently used to prevent polymerization and get soluble molecular precursors with low-valent metal cations such as Cu + in the sol-gel synthesis of advanced ceramics such as high Tc superconductors YBa2Cu307 j (see Sulfur Organic Polysulfanes) ... 

To begin with, phosphates come in various kinds. Phosphoric acid contains three hydroxy groups and can form esters in which one, two, or three of these have been replaced by alkoxy groups. Phosphoric acid is highly acidic, and so are the... 

Alcoholysis of the aconitines proceeds in the alcohol at elevated temperatures (ca. 125°) with replacement of the acetate group by the alkoxy group (38, 39) thus, in methanol a methyl ether results, which is a methyl ether of the benzoate (or other monoester) of the parent amino alcohol. On hydrolysis (39) methanol is split off as well as the acyl grouping and the parent amino alcohol is obtained the ready fission of the new ether grouping is noteworthy. 

The products of the reaction between P3N3Cl4(N=PCl20H)2 and substituted sodium phenoxides are either amorphous solids or viscous liquids with the formula P3N3(OAr)4[N==P(OAr)20H]2, and similar alkoxy-sub-stituted compounds react with triphenylchlorosilane to replace one alkoxy-group in a side-chain by OSiPha. ... 

The scope of this method was extended to include a donor/acceptor-type conjugated polymer by replacing the alkoxy group with an alkylthienyl group on the donor unit BDT (Huo et al., 2011). The 2-D conjugated 81a and 81b (Fig. 2.4B) exhibited higher thermal... 

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