Vinyl ethers methoxylation

It should be noted, in addition, that the resonances of the vinylic protons and the methoxyl group in the vinyl ether 151 are observed33 at considerably lower field as compared with the vinylthio derivatives, and this indicates a shielding effect of the sulfur atom. 

Considerable progress has been made in recent years regarding the anodic oxidation of unsaturated ethers. In earlier studies, it was found that anodic methoxylation of simple vinyl ethers was a preparatively useful transfoimation, being essentially analogous to the anodic methoxylation of anisole derivatives, as in the preparation of 1-ethoxy-1,2-dimethoxyethane from ethyl vinyl ether [143] ... 

Figure 1-23 indicates only one methoxyl band is interacting with the polystyrene phenyl group, even though there are two distinct IR contributions of poly(vinyl methyl ether) methoxyl groups, as already shown in Figure 1-22. The other methoxyl band of poly(vinyl methyl ether) at 2824 cm is asynchronously correlated with the phenyl bands of the polystyrene component (Figure 1-24). This result suggests that while one component of poly(vinyl methyl ether) methoxyl groups...

Figure 1-23. A synchronous 2D IR spectrum of a blend comparing the reorientational motions of transition dipoles associated with the polystyrene phenyl and poly(vinyl methyl ether) methoxyl groups [57).

Wouldn t the methoxyl group of methyl vinyl ether act in the same way Oxygen is also more electronegative than carbon, and wouldn t this difference in electronegativity act to discourage any addition that puts more positive charge on the already... 

Further investigation by Chapman and co-workers using physical methods has revealed that a-lumicolchicine is a dimer of j3-lumicol-chicine (57). UV- and IR-spectra showed the absence of an enol ether group and indicated the presence of only the styrene chromophore. The NMR-spectrum of a-lumicolchicine is similar to that of j8-lumicolchicine except that (1) the vinyl proton observed in jS-lumicolchicine is missing, (2) a-lumicolchicine exhibits one more aliphatic proton than the ]8-isomer, and (3) the methoxyl resonance at 3.63 ppm in j8-lumicolchicine has shifted to unusually high field in a-lumicolchicine (3.02 ppm). This... 

Interestingly, polystyrene and poly(vinyl methyl ether) are very different polymers. Polystyrene is a hard hydrophobic plastic resin, while poly(vinyl methyl ether) is a soft water-soluble polymer. It is quite surprising that such a pair of polymers could produce a molecularly mixed homogeneous one-phase system. The specific origin of the miscibility of this polymer pair is not well understood, although some level of interaction is speculated between the methoxyl groups of poly(vinyl methyl ether) and the phenyl groups of polystyrene [54]. 

Figure 1-22. An asynchronous 2D IR spectrum for the methoxyl vibration of a blend of backbone-deuterated polystyrene and poly(vinyl methyl ether) [57],...

Such a specific interaction most likely involves the lone-pair of electrons on the methoxyl oxygen atom of poly(vinyl methyl ether) and Jt-electrons of the polystyrene phenyl groups [54],... 

In 2012, Fukuyama s group reported a novel synthesis route to the spiro-p-lactonic sesquiterpene (-)-anisatin, and they also relied on the construction of a bicyclo[2.2.2]octane system via a DIB-mediated methoxylative phenol dearomatization followed by an intramolecular Diels-Alder reaction [127]. The homochiral phenolic dihydrobenzofuran propargyl ether 231 thus afforded, via the ort/io-quinone monoketal 232 and treatment of its intramolecular [4+2] epimeric cycloadducts with camphorsulfonic acid in MeOH, the bicyclo[2.2.2] octanedienone 234 as a single diastereomer (Fig. 56). Further transformation of 234 gave the vinyl 235, whose trisubstituted double btmd bridge was oxidatively cleaved by mild ozonolysis to furnish the ketoaldehyde 236, en route to (-)-anisatin [127]. 

Poly(vinyl methyl ether) (PVME) also has a LCST of about 37°C in aqueous media and is a thermosensitive polymer. PVME molecules dissolve in water owing to the formation of hydrogen bonding between methoxyl groups and water molecules at low temperatures. When the solution is... 

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