Propyl propenyl ether

Problem 14.45 Give the structural formula and lUPAC name for (a) n-propyl propenyl ether, (b) isobutyl terf-butyl ether, (c) 12-crown-4 ether. M... 

The characteristics of the 1,3-dipolar cycloaddition mechanism of azides and other 1,3-dipoles (such as diazoalkanes, azo-methine imines, nitrones, nitrile imines, nitrile oxides) have been described in detail by Huisgen.191 19 According to the author, the addition of a 1,3-dipole (a b c) to a dipolarophile (d e) occurs by a concerted mechanism in which the two new a bonds are formed simultaneously although not necessarily at equal rates (32). As a consequence, a stereoselective cis addition is observed. Thus, the addition of p-methoxyphenyl azide to dimethyl fiynarate (33) yields l-(p-methoxyphenyl)-4,5-froiw-dicarbomethoxy-AMriazoline (34),194 and 4-nitrophenyl azide gives exclusively the respective cis-addition products 35 and 36 on addition to irons- and cis-propenyl propyl ether.196... 

Numerous [2 + 2] cycloadditions which may proceed through dipolar intermediates (tetramethylenes which may be represented as resonance hybrids of singlet diradicaJ and zwitterionic forms) react with partial or even complete loss of the stereochemical relationships present in starting materials. Reactions between the cis and trans isomers of l,2-bis(trifluoromethyl)-l,2-dicyanoethylene and cis- and trans-propenyl n-propyl ether are not completely stereoselective. The trans electrophilic alkene (107) and the cis isomer of the enol ether (108), for instance, give rise to products (109), (110) and (111), the last having trifluoromethyl groups in cis relationship one to the other. ... 

Stereospecific 1,2-cycloadditions are given by cis and trans propenyl propyl ether with diphenylketene and dimethylketene - , and furthermore by diphenylketene with cis- and trflni-2-butene and by dichloroketene with cis- and trani-cyclooctene . Stereospecific means that contamination by the other isomer was not found the available methods would have detected a few percent of it, and in the most favourable case even 1%. 

Comparing cis and trans isomers of propenyl propyl ether in their reactivity towards diphenylketene, a ratio kcislknans of about 180 has been found (in PhCN, 40°C) , confirmed by the value of 172 20 from experiments without solvent with dimethylketene the ratio is 60 10 . The opposite phenomenon has been observed in Diels-Alder reactions of fumarate/maleate and other 1,2-disubstituted ethylenes (Section 4.1.3). The fact that cis isomers are thermodynamically less stable than trans isomers seems to prevail in determining relative reactivities of these 1,2-cycloadditions. 

Poly(phenyl vinyl sulfide-alt-MA), 386 Polyphosphoric acid, dehydrating agent, 80, 84 Poly03-pinene-alt-MA), 352 Poly(propenyl chloride-alt-MA), 380 Poly(c -propenyIphenol-ait-MA), 375 Poly(4-propenylpyrocatechol-alt-MA), 375 Poly(propenylthiophene-co-MA), 387 Poly(cw-propenyl vinyl ether-co-MA), 326 Poly (/I-propyl endomethylene tetrahydrophthalate-co-MA), 289 Polypropylene, 461-464 MA copolymer blends, 292 MA ene adduct, 175 bismaleimide blends, 464 MA grafting procedures, 675... 

Propenyl phenyl sulfone added gradually to LiAlH4 in abs. ether, and refluxed 1 hr. propyl phenyl sulfone. Y 93%. F. e., also reduction to ethylenethio-ethers, 1-thiaindenes, s. E. N. Karaulova, D. S. Meflanova, and G. D. Garpern, 29, 662 (1959) C. A. 54, 446a. 

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