Vinyl phenyl ether

That electrocyclic reaction is related to the Claisen rearrangement of phenyl vinyl ether. In a final step a cyclization takes place with subsequent elimination of ammonia to yield the indole 2 ... 

The orfho-Claiscn rearrangement of phenyl vinyl ether 8 to 2-vinylphenol 9 (Scheme 4.5) is a very slow reaction, requiring 80 h of reflux in DMF to give a yield of only 34%. Using the CEM microwave system an 80% yield was obtained in 5 h at 196 °C and 200 kPa [6],... 

Scheme 4.5 Rearrangement of phenyl vinyl ether to 2-allylphenol.

Phenyl-1 -propanone 1 - Pheny 1-2-propanone Phenyl salicylate Phenyl vinyl ether Phthalamide 1.3- Phthalic acid 1.4- Phthalic acid Phthalic anhydride Phthalonitrile Piperidine 14.85... 

Some obscurities. Each of the reactions mentioned has been identified in at least one system, but there are very many obscurities to be cleared up. For example, transfer by methyl vinyl ether, phenyl vinyl ether, vinyl acetate and some of the corresponding polymers in the polymerization of styrene by stannic chloride has been studied, but the mechanism is not at all clear [124]. 

We report on the measurement of the propagation rate constants kp of styrene, indene, phenyl vinyl ether (PhViE) and 2-chloroethyl vinyl ether (CEViE) in nitrobenzene at (mostly) 298 K with 4-ClC6H4CO+SbF 6 as initiator. The dependence of the conductivity on the [4-ClC6H4CO+SbF"g] = c0 helped to establish that [Pn+] = c0 and thus to validate the foundation of this work. It is shown that most probably the propagating species are the uncomplexed, unpaired, solvated carbenium ions. Some new enthalpies of polymerisation have been found. 

This is the third report on attempts to measure the propagation rate constant, kp+, for the cationic polymerisation of various monomers in nitrobenzene by reaction calorimetry. The first two were concerned with acenaphthylene (ACN) [1, 2] and styrene [2]. The present work is concerned with attempts to extend the method to more rapidly polymerising monomers. With these we were working at the limits of the calorimetric technique [3] and therefore consistent kinetic results could be obtained only for indene and for phenyl vinyl ether (PhViE), the slowest of the vinyl ethers 2-chloroethyl vinyl ether (CEViE) proved to be so reactive that only a rough estimate of kp+ could be obtained. Most of our results were obtained with 4-chlorobenzoyl hexafluoroantimonate (1), and some with tris-(4-chlorophenyl)methyl hexafluorophosphate (2). A general discussion of the significance of all the kp values obtained in this work is presented. 

Table 3 The polymerisation of phenyl vinyl ether by (1) in PhN02 at 293 K ... 

For the addition of ethylene, EtOAc as solvent was particularly advantageous and gave 418 in 60% yield (Scheme 6.86). The monosubstituted ethylenes 1-hexene, vinylcyclohexane, allyltrimethylsilane, allyl alcohol, ethyl vinyl ether, vinyl acetate and N-vinyl-2-pyrrolidone furnished [2 + 2]-cycloadducts of the type 419 in yields of 54—100%. Mixtures of [2 + 2]-cycloadducts of the types 419 and 420 were formed with vinylcyclopropane, styrene and derivatives substituted at the phenyl group, acrylonitrile, methyl acrylate and phenyl vinyl thioether (yields of 56-76%), in which the diastereomers 419 predominated up to a ratio of 2.5 1 except in the case of the styrenes, where this ratio was 1 1. The Hammett p value for the addition of the styrenes to 417 turned out to be -0.54, suggesting that there is little charge separation in the transition state [155]. In the case of 6, the p value was determined as +0.79 (see Section 6.3.1) and indicates a slight polarization in the opposite direction. This astounding variety of substrates for 417 is contrasted by only a few monosubstituted ethylenes whose addition products with 417 could not be observed or were formed in only small amounts phenyl vinyl ether, vinyl bromide, (perfluorobutyl)-ethylene, phenyl vinyl sulfoxide and sulfone, methyl vinyl ketone and the vinylpyri-dines. 

The relative stability of l, 2 -epoxyvinylbital, and the great instability of its diol, can be gainfully compared with the fate of the corresponding metabolites of phenyl vinyl ether (10.69, R = H) and 4-nitrophenyl vinyl ether (10.69, R = N02), two mutagenic and tumorigenic compounds [144] [145]. Their primary metabolic route is by vinyl epoxidation to the corresponding... 

Thus, a wide variety of vinyl ethers could be synthesized using this method (Scheme 10.5). This catalyhc vinylation system was found to be applicable to the synthesis of vinyl ethers from secondary and tertiary alcohols. No deuterium was introduced into the resulhng phenyl vinyl ether when phenol-d was allowed to... 

It was found that a mixture of 4-vinylpyridine with p-chlorostyrene copolymerizes without any initiator in the presence of poly(maleic anhydride) at 50°C in DMF. The fact that poly(maleic anhydride) cannot initiate the polymerization of styrene or phenyl vinyl ether shows that poly(maleic anhydride) does not act as a normal anionic or cationic initiator. The compositions of copolymers obtained with various initial compositions of... 

Phenyl vinyl ethers 1 undergo regiospecific but not stcreospecific dimerization to give a mixture of cisjtransA, 2-disubstituted cyclobutanes 2 and 3 on irradiation in the presence of dimethyl terephthalate in acetonitrile.5... 

Cyclodimerization of Phenyl Vinyl Ethers 1 General Procedure 5... 

A solution of the appropriate phenyl vinyl ether (1, 0.05 mol) and dimethyl terephthalate (3.4 g, 0.02 mol) in MeCN (150 mL) was irradiated for 15 h with a 500-W high-pressure Hg arc through Pyrcx under N2 at rt. After evaporation of the solvent in vacuo, the resulting precipitate of dimethyl terephthalate was removed by filtration and washed with a few portions of cooled Et20. The filtrate combined with the Et20 portions was concentrated and distilled under reduced pressure to recover unreacted starting material and the brown-colored oily residue chromatographed (silica gel, benzene/petroleum ether 1 49) to yield a mixture of cyclobutanes 2 and 3. 

The scope and utility of cation radical induced cyclobutanation1 is greatly enhanced by the option of cross additions, the first of which was the formation of a 3 2 mixture of diastereomeric cyclobutanes in the irradiation of an equimolar mixture of phenyl vinyl ether and 1,1-dimethylindene in the presence of tetraphenylpyrylium tetrafluoroboratc in acetonitrile.2 The scope of PET cyclobutanations was further extended in a synthetic sense by the observation of cross additions of electron-rich alkenes to conjugated dienes.3 4 Examples of such reactions are shown below in the formation of compounds 1, 2, 3 and 4. 

In contrast to these ring openings, only ring closure could be observed in the photodimerization of phenyl vinyl ether, Eq. (40), which proceeded only in one direction... 

The photocyclodimerization of JV-vinylcarbazole, which was reported by Ledwith and Shirota, can be accounted for by this mechanism [71-73]. A chain process is involved in this photoreaction, and the quantum yield exceeds unity (the maximum quantum yield is 66). The hole transfer from the cyclobutane radical cation to a neutral JV-vinylcarbazole is a key reaction for the chain process. Similar photodimerizations of electron-rich alkenes such as aryl vinyl ethers [74-76], indenes [29, 77, 78], styrenes [79-80] and enamines [71] have been reported by several groups. The DCA-sensitized photodimerization of phenyl vinyl ether gives cis- and trans-1,2-diphenoxycyclobutanes. This photoreaction also involves a chain process although the chain length is short [75]. 

Transition metal complexes and semi-conductors can also be used as electron accepting photosensitizers for the photocyclodimerization of phenyl vinyl ether [81-82]. 

Farid reported that the crossed addition of 1,1-dimethylindene with phenyl vinyl ether occurs upon irradiation of their acetonitrile solution in the presence... 

Photocycloaddition via triplexes is a new area in organic photochemistry. As mentioned in Sect. 3.4, phenyl vinyl ether undergoes photocyclodimerization... 

The nitrone of piperidine reacts with phenyl vinyl ether to yield a 1,3-dipolar cycloaddition product. Benzylation led to a ring-opened product which was converted to a hydroxamic acid. This is desired functionality in medicinal chemistry because it is a metal-binding ligand <03S1221>. 

Two techniques are commonly used in the preparation of olefinic ethers from halo ethers. The first involves heating a /5-halo ether with fused or powdered potassium hydroxide. This method is typified by the conversion of -phenoxyethyl bromide to phenyl vinyl ether (69%) and, /5 -dichlorodiethyl ether to divinyl ether (61%). In the latter case, yields are improved in the presence of ammonia gas. In the second procedure, an aliphatic or aromatic chloro ether is heated with pyridine to 115°. This method is of value in the preparation of several methoxystyrenes. Chloroalkylation of the aromatic ether is followed by dehydrohalogenation. 

The ubiquitous and reversible formation of radical cations in photoelectrochemical transformations allows pericyclic reactions to take place upon photocatalytic activation since the barriers for pericyclic reactions are often lower in the singly oxidized product than in the neutral precursor. For example, ring openings on irradiated CdS suspensions are known in strained saturated hydrocarbons [176], and formal [2 -I- 2] cycloadditions have been described for phenyl vinyl ether [ 177] and A-vinyl carbazole [178]. The cyclization of nonconjugated dienes, such as norbomadiene, have also been reported [179]. A recent example involves a 1,3-sigmatropic shift [180]. 

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