Of -diallylic ether

Dining preparation of diallyl ether by dehydration of the alcohol with sulfuric acid, a violent explosion may occur (possibly involving peroxidation and certainly... 

Y represents an oxygen atom or a single chemical bond. In the case of diallyl ether double bond isomerization occurs to a considerably higher extent, easily reaching 20 - 30 mole percent [9]. Obviously, reactive terminal C=C double bonds are required to get fast reaction with hydrosiloxane crosslinkers, whereas isomeric inner double bonds exhibit too low a reactivity to be of importance. Another strategy may be helpful. 

During the study of the isomerization of diallyl ether with catalysts of this type, it was observed that the nature of the complex anion (Y) has a profound influence on the relative rate of isomerization with respect to cyclization. Diallyl ether can be isomerized to a mixture consisting mainly of allyl propenyl ethers (44) with a small amount of 2-methyl-3-methylene-tetrahydrofuran (45) and dipropenyl ether (46) the catalyst for this... 

Asymmetric Cyclizations of 1,6-Heptadiene and of Diallyl Ether Using Catalyst Modified with Epimers of MENTHYL-rerf-BuTYLMETHYLPHospHiNE... 

Failure to achieve the bicyclization of diallyl ether with nBu2ZrCp2 led to the unexpected discovery of the oxidative addition reaction,226 shown in Scheme 44. This reaction has been extensively used for developing synthetically useful reactions, also shown in Scheme 44 232 234>234a-234c Another breakthrough on this topic was made with alkenyl chloride,235 which led to more recent similar discoveries with alkenyl sulfides, sulfones, and ethers236,23611 237 (Scheme 45). 

For synthetic purposes, the conversion of diallyl ether (11, X = O) to 3-oxabicy-clo[3.2.0]heptane (12, X = O),11 of ethyl JV,7V-diallylcarbamate (11, X = NC02Et) to A7-car-boethoxy-3-azabicyclo[3.2.0]heptane (12, X = NC()2Et)12 and of 4-hydroxyhepta-l,6-diene (13) to 3-hydroxybicyclo[3.2.0]heptane (14)13 have become the most useful copper(I)-photocat-alyzed (intramolecular) cyclodimerizations of alkenes. 

To a solution of diallyl ether (11. X = O 980 mg, 0.01 mol) in anhyd Et20 (140 mL) was added CuOTf (36 mg, 0.1 mmol). This homogeneous solution was irradiated under a N2 atmosphere with a medium-pressure Hg lamp for 20 h. After completion of the reaction the Et20 solution was poured into a mixture of crushed ice and 30% NH4OII (100 mL) and shaken well. The two layers were separated and the Et20 layer dried (MgS04). Distillation gave 12 (X = O) yield 51 mg (52%) bp 115-118 °C. 

FIGURE 2. 50 MHz 13C NMR spectrum of the equilibrium products of metathesis reactions of diallyl ether catalysed by 8 (R = Me). Peaks 1 and 2 2,5-dihydrofuran. Peaks 3 and 4 linear polymer (ca 100% tram). Peaks a, b and c end-group carbons, a —CH2CH=CH2, b —CH2CH=CH2 and c -CH2CH=CH2- Solvent CDCI3. Reproduced by permission of Hiithig Wepf Publishers, Zug, Switzerland, from Ref. 262... 

Efficient synthesis of 7- 20-iuembered crown ethers 122 having a trans-alkene bond was achieved by the Ru-catalysed metathesis of diallyl ethers 121 [46]. A remarkable... 

Transformations shown in Schemes 12-14 constitute the first examples of catalytic AROM reactions ever reported. Meso-triene 50 is converted to chiral heterocyclic triene 51 in 92% ee and 68% yield with 5 mol% 4a (Scheme 12) [21]. Presumably, stereoselective approach of the more reactive cydobutenyl alkene in the manner shown in Scheme 12 (II) leads to the enantioselective formation of Mo-alkylidene III, which in turn reacts with an adjacent terminal olefin to deliver 51. Another example in Scheme 12 involves the net rearrangement of meso-bicycle 52 to bicyclic structure 54 in 92% ee and 54% yield. The reaction is promoted by 5 mol% 4a and requires the presence of diallyl ether 53 [22], Mechanistic studies suggest that initial reaction of 53 with 4a leads to the formation of the substantially more reactive chiral Mo=CH2 complex (vs neophylidene 4a) which can react with the sterically hindered norbornyl alkene to initiate the catalytic cycle. 

Scheme 15 Copper catalyzed photocycloaddition of diallyl ether.

Under much more drastic conditions, at 200 °C RuCl2(PPh3)3 promotes the isomerization of diallyl ethers into aldehydes [66], and under 50 bar of... 

The reaction of diallyl ether with mercury(II) nitrate in dichloromethane in the presence of an alkyl carbamate proceeds with total stereoselectivity and moderate yield. Under these conditions (thermodynamic control) the reaction gave, after reductive cleavage, the more stable diequatorial alkyl 3,5-dimelhyl-4-morpholine carboxylate 1124. 

Stereospecific formation of a cis-fused octahydroquinoline (226 85%) is depicted in Scheme 47, which also shows the conversion of diallyl ether (227) into a 1 1 cisitrans mixture of tetrahydrofiirans (228 75%). It is worth noting that analogous nickel(0)-catalyzed cyclization of the corresponding acetate gave exclusively the trans isomer of (228). ... 

Table 12 Diastereoselectivity in 2,3-Wittig Reanangcment of Diallylic Ethers...

Scheme 9 Envelope transition states for 2,3-Wittig rearrangements of diallylic ethers leading to diastereomeric and enantiomeric products...

The l,5-dien-3-ols produced by 2,3-Wittig rearrangement of diallylic ethers can serve as pivotal intermediates for further elaboration through tandem or sequential 3,3-sigmatropic reactions. " The three sequences examined to date are summarized in Scheme 10. 

Photolysis of methyl a-(phenylseleno)acetate in the presence of diallyl ether and carbon monoxide leads to the acyl selenides via radical cyclization and group transfer carbonylation (Scheme 15.49) [124]. 

A synthesis of ( )-l-triorganosilyl-l-alkenes by hydrosilylation of l-aUcynes can be accomplished in the presence of a carbene-Pt complex in which the metal is also ligated to the two double bonds of diallyl ether. ... 

Na-sand prepared in octane under Nz, octane replaced by hexane, a soln. of diallyl ether in hexane added over a period of 1 hr. at 35° with rapid stirring, which is continued for an additional 30 min., then a soln. of 2-bromooctane in hexane added dropwise at 0° with stirring over a period of 30 min., stirring continued for 1 hr. at 0 , then for another 20 min., while the mixture warms to room temp., allowed to stand overnight, and again stirred for 1 hr. —4-methyl-l-decene. Y 71%. (R. L. Letsinger and J. G. Traynham, Am. Soc. 70, 3342 (1948).) s. a. 3, 690... 

Bis-(3-chloro-2-hydroxypropyl) ether 273 C02 is led into a mixture of diallyl ether (0.25 mole), water (2.5 1), and 35 % calcium hypochlorite solution (102 g, 0.25 mole) at 3° with stirring and cooling. A dry-ice condenser is placed on the reaction flask to prevent loss of diallyl ether. The hypochlorite is consumed in 2 h, then a further amount (51 g) is added and C02 is passed in with stirring for a further 2 h. The solution is filtered from CaC03, saturated with NaCl, and extracted with ether. The yield is 94.4% and the b.p. is 150-165°/3 mm or, after a further distillation (138-139°/1 mm). 

Examples of such reactions are shown in Table 8.5. Divinyl ether is unreactive but diallyl ether, when treated in bulk with 8, gives an equilibrium mixture of 63% 2,5-dihydrofuran and 37% of its -trans, ring-opened polymer, albeit of low MW (Fig. 8.3). The analogous tungsten complex is not a good initiator for the ADMET polymerization of diallyl ether. 

Other Systems.—An oxaselenepan (195) is formed as the primary product by intramolecular oxyselenation in the reaction of diallyl ether with potassium selenocyanate in methanol, in the presence of copper(ii) chloride.A range of... 

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