2- ethyl vinyl ether preparation

Hate 1. This excess was used to be absolutely sure that all a-chloroether would have reacted. Traces of this compound, if still present in the reaction mixture, will hydrolyse during the aqueous work up. The acid that is liberated can cause hydrolysis of the product to H2C=CH-C(=0)CH(CH3)0C2H5. HoLp. A. Prepared by introducing 0.30 mol of dry gaseous HCl (weight increase) into 45 ml of freshly distilled ethyl vinyl ether (excess) at -30°C. 

Ethyl vinyl ether was the first to be prepared, in 1878, by treatment of diethyl chloroacetal with sodium (216). Methyl vinyl ether was first Hsted in Reppe patents on vinylation in 1929 and 1930 (210,211). 

The ethoxyethyl ether is prepared by acid catalysis from a phenol and ethyl vinyl ether and is cleaved by acid-catalyzed methanolysis. ... 

More recently, further developments have shown that the reaction outlined in Scheme 4.33 can also proceed for other alkenes, such as silyl-enol ethers of acetophenone [48 b], which gives the endo diastereomer in up to 99% ee. It was also shown that / -ethyl-/ -methyl-substituted acyl phosphonate also can undergo a dia-stereo- and enantioselective cycloaddition reaction with ethyl vinyl ether catalyzed by the chiral Ph-BOX-copper(ll) catalyst. The preparative use of the cycloaddition reaction was demonstrated by performing reactions on the gram scale and showing that no special measures are required for the reaction and that the dihydro-pyrans can be obtained in high yield and with very high diastereo- and enantioselective excess. 

The reactants can be made from allylic alcohols by mercuric ion-catalyzed exchange with ethyl vinyl ether.220 The allyl vinyl ether need not be isolated and is often prepared under conditions that lead to its rearrangement. The simplest of all Claisen rearrangements, the conversion of allyl vinyl ether to 4-pentenal, typifies this process. 

The preparation of resin-bound nitroalkenes via a microwave-assisted Knoevenagel reaction of resin-bound nitroacetic acid with aryl and alkyl substituted aldehydes is reported. The potential of these resin-bound nitroalkenes for application in combinatorial chemistry is demonstrated by a Diels-Alder reaction with 2,3-dimethylbutadiene (Scheme 8.9). It is also used for one-pot three-component tandem [4+2]/[3+2] reactions with ethyl vinyl ether and styrene 46... 

The pyranocoumarin 105 can be prepared via a three-component Diels-Alder reaction between 4-hydroxycoumarin, ethyl vinyl ether and an a-dicarbonyl compound. Similarly to the above, upon treatment of 105 with sulfuric acid in THF, hydrolysis and rearrangement occur to give the furofurochromenone 106. The hemiacetal functionality in 106 may then be oxidized with pyridinium chlorochromate (PCC) to give the lactone 107 <2001EJ03711> (Scheme 28). 

This compound is prepared by the addition of ethyl vinyl ether to acrolein, under conditions similar to those described for a similar addition of methyl vinyl ether to crotonaldehyde in Org. Syntheses, 34, 29 (1954) see Longley and Emerson, J. Am. Chem. Soc., 72, 3079 (1950). Glutaraldehyde is available currently as a 30% aqueous solution from the Carbide and Carbon Chemicals Company, 30 East 42nd Street, New York. 

Styrene was purified and dosed as described [2]. Indene (99% + pure, Aldrich, Gold Label) was dried on CaH2 and dosed into evacuated phials. Ethyl vinyl ether and CEViE were Aldrich products. They were dried on CaH2 and used without further treatment. PhViE was prepared and purified essentially according to the method described [6] and stored over CaH2. 

Recently, the first examples of catalytic enantioselective preparations of chiral a-substituted allylic boronates have appeared. Cyclic dihydropyranylboronate 76 (Fig. 6) is prepared in very high enantiomeric purity by an inverse electron-demand hetero-Diels-Alder reaction between 3-boronoacrolein pinacolate (87) and ethyl vinyl ether catalyzed by chiral Cr(lll) complex 88 (Eq. 64). The resulting boronate 76 adds stereoselectively to aldehydes to give 2-hydroxyalkyl dihydropyran products 90 in a one-pot process.The diastereoselectiv-ity of the addition is explained by invoking transition structure 89. Key to this process is the fact that the possible self-allylboration between 76 and 87 does not take place at room temperature. Several applications of this three-component reaction to the synthesis of complex natural products have been described (see section on Applications to the Synthesis of Natural Products ). 

Meyers and Shimano discovered the unusual deprotonation behavior of ethoxy-vinyllithium-HMPA complex (EVL-HMPA) for the deprotonation of the trans-oxazoline 366 and the cw-oxazoline 367. The EVL-HMPA complex is prepared by deprotonation of ethyl vinyl ether with ferf-butyllithium in THE followed by addition of HMPA. Reaction of the frani-oxazoline 366 with both the EVL-HMPA complex and conventional alkyllithium reagents (RLi) resulted in deprotonation at the benzylic 5-position. In contrast, deprotonation of 367 occurred at the 4-position with an alkyllithium reagent RLi, whereas benzylic deprotonation predominated with the EVL-HMPA complex (Scheme 8.117). ° The authors proposed that EVL-HMPA complexes with the 5-phenyl substituent prior to deprotonation. 

The procedure below is the most convenient and quick way to prepare ethoxyethyne [24). Yields are usually excellent provided that the Z-isomer is the major component in the mixture of isomers of the bromovinyl ether. The E-isomer remains unchanged under the conditions of the elimination (rule of trans-elimination). The bromovinyl ether can be prepared in good yields starting from ethyl vinyl ether. 

Prepared by addition of CH3G C(CHj)(OH)CH2CH(OCH3)2 (p. 86) to ethyl vinyl ether (for this procedure see p. 265). 

The 1,4- and 1,5-benzothiazepines (421) and (423) have been prepared by the photochemical reactions of the benzoisothiazole (420) and the benzothiazole (422) respectively with ethyl vinyl ether (81TL529, 2081). The mechanisms of these reactions are not fully established but it is interesting to note that the reactions of (422) with cis- and trans-but-2-ene are stereospecific. 

Materials. CEVE and 4-nitrophenyl vinyl ether (VNP) were synthesized and purified as reported earlier (12,13), respectively. 2-(4-Nitrophenoxy)ethyl vinyl ether (NPVE) (m.p. 72-73°C) was prepared by reacting of potassium 4-nitrophenoxide (PNP) (142 g 0.8 mol) and CVE (842 g 7.9 mol) using tetra-n-butylammonium bromide (TBAB) (4.0 g 12 mmol) as a phase transfer catalyst at the boiling temperature of CVE for 12 h. The potassium chloride produced was filtered off, the filtrate washed with water, excess CVE evaporated, and then the crude product was recrystallized twice from n-hexane. (Yield 61.7%. IR (KBr) 1630 (C=C), 1520 (-N02), and 1340 cm-1 (-N02).) Elemental analysis on the product provided the following data Calculated for C10HnNO4 C, 57.40%, H, 5.30%, N, 6.69%. Found C, 57.49%, H, 5.3%, N, 6.72%. 

The reactions of PCVE with PNP are quantitative under these reaction conditions, and polymeric photosensitizers such as poly[2-chloro-ethyl vinyl ether-co-2-(4-nitrophenoxy)ethyl vinyl ether] (PCVE-NPVE) containing about 4, 10, 19, 28, 37, and 46 mol-% of pendant 4-nitrophenoxy (NP) groups were prepared (Table II). Although the reactions of PCVE with PNN were carried Table II. Reaction Condition and Results of the Syntheses... 

The synthesis of epoxy ethers by peroxy acid treatment of suitable vinylic ethers, on the other hand, is complicated by the acid sensitivity of epoxy ethers. For example, Bergmann and Mk>keley1Ss claimed in 1921 to have prepared 1 -ethoxy-1 (2 -epoxyethane by the oxidation of ethyl vinyl ether with perbenzoic aoid, bat B years later modified their structure to a dioxone type of dimer.186 In 1 B0 Mous-seron and co-wcrkere1168-1184 reported the preparation of an epoxy ether from 1 -ethoxy-1 -eydohexene, but 4 years later Stevens and Taznma164 showed the compound obtained in this oxidation, not to have the structure initially assigned to it. 

The acetal was likewise prepared from chloroacetal and [Rh(OEP)]-, the aldehyde from [Rh(OEP)]2 and ethyl vinyl ether [326]. 

Most of the reported polyfvinyl ether) macromonomers have been prepared with a methacrylate end group which can be radically polymerized and which is non-reactive under cationic polymerization conditions [71-73]. Generally, the synthesis was based on the use of the functional initiator 30, which contains a methacrylate ester group and a function able to initiate the cationic polymerization of vinyl ethers. Such initiator can be obtained by the reaction of HI and the corresponding vinyl ether. With initiator 30 the polymerization of ethyl vinyl ether (EVE) was performed using I2 as an activator in toluene at -40 °C. The MW increased in direct proportion with conversion, and narrow MWD (Mw/Mn= 1.05-1.15) was obtained. The chain length could be controlled by the monomer to initiator feed ratio. Three poly(EVE) macromonomers of different length were prepared by this method Mn=1200,5400, and 9700 g mol-1. After complete... 

Fig. 14.47. Preparation of an allyl vinyl ether, D, from allyl alcohol and a large excess of ethyl vinyl ether. Subsequent Claisen rearrangement D C...

The preparation involves an oxymercuration (Section 3.5.3) of the C=C double bond of the ethyl vinyl ether. The Hg(OAc) ion is the electrophile as expected, but it forms an open-chain cation A as an intermediate rather than a cyclic mercurinium ion. The open-chain cation A is more stable than the mercurinium ion because it can be stabilized by way of oxocarbe-nium ion resonance. Next, cation A reacts with the allyl alcohol, and a protonated mixed acetal B is formed. Compound B eliminates EtOH and Hg(OAc) in an El process, and the desired enol ether D results. The enol ether D is in equilibrium with the substrate alcohol and ethyl vinyl ether. The equilibrium constant is about 1. However, the use of a large excess of the ethyl vinyl ether shifts the equilibrium to the side of the enol ether D so that the latter can be isolated in high yield. 

Bromobis[2,3-butanedione dioximato( 1 -)] (4-terf-butylpyridine)cobalt(lIl) is a tan, microcrystalline solid with greatly enhanced solubility in organic solvents compared to the chloro(pyridine) analogue. It is also the compound of choice in preparing alkylcobaloximes by the subsequent procedure because of the ease of isolation of the resultant products. In addition, the bromo(4-ferf-bupy) species react directly with electron-rich olefins, such as ethyl vinyl ether, in the presence of ethanol to yield, in this case, bis[2,3-butanedione dioximato(l-)]-(2,2-diethoxyethyl)(pyridine)cobalt(III).1J Conversion of the dimethyl sulfide compound to the pyridine derivatives is readily detected by a characteristic infrared absorption at 1600 cm 1 (pyridine stretch). The H nmr spectrum of bromobis[2,3-butanedione dioximato(1 -)] (4-ferf-butylpyridine)cobalt (III) has absorptions in the alkane region in the ratio of 3 4 at 6 1.25 ppm [Py—C (CH3)3 ] and 6 2.43 ppm (dh—CH3) from tetramethylsilane. 

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