Divinyl dichloride

As a test of the intermediacy of the divinyl dichloride (44) in the solvolysis of dichlorocyclopropylcar-binols, Hiyama prepared the homoallylic alcohols (48) by additirai of l,l-cyclic ketones. Treatment of (48) with trifluoroacetic acid produced the cyclopentenones in very good yield (equation 31). This reaction presumably proceeds by dehydration to the divinyl dichloride followed by a similar ionization-cyclization sequence, foterestingly the regioisomeric dichloride also underwent closure to a cyclopentenone. ... 

In a related study Gaioni generated the divinyl dichloride by cheletropic extrusion of sulfur dioxide from the dichlorocarbene/3-sulfolene adduct (49). Under the reaction conditions the divinyl dichloride solvolyzes to the cyclopentenone as outlined previously (equation 32). 

Methylenebis(oxy) ]bis(2-chloroformaldehyde), see Bis (2-chloroethoxy) methane Methylene chlorobromide, see Bromochloromethane Methylene dichloride, see Methylene chloride Methylene dimethyl ether, see Methylal Methyl 2,2-divinyl ketone, see Mesityl oxide Methylene glycol, see Formaldehyde Methylene glycol dimethyl ether, see Methylal Methylene oxide, see Formaldehyde Methyl ethanoate, see Methyl acetate (1 -Methylethenyl)benzene, see a-Methylstyrene Methyl ethoxol, see Methyl cellosolve 1-Methylethylamine, see Isopropylamine (l-Methylethyl)benzene, see Isopropylbenzene Methylethyl carbinol, see sec-Bntyl alcohol Methyl ethylene oxide, see Propylene oxide ds-Methylethyl ethylene, see cis-2-Pentene frans-Methylethyl ethylene, see frans-2-Pentene Methyl ethyl ketone, see 2-Bntanone Methylethylmethane, see Butane... 

AH- Thiopyrans are directly accessible only in relatively poor yield, and then only by condensation of a suitable 1,5-dicarbonyl compound with sulfide (690PP21). As has been described earlier, this particular reaction is bedevilled with the problem of disproportionation to tetrahydrothiopyrans and thiopyrylium compounds. Thiopyran-4-ones may be prepared in a related manner by addition of sulfur dichloride to divinyl ketones, followed by base treatment (76MI22500). 

Vinylboronic acids undergo analogous reactions to give the mono- and divinyl-thallium derivatives in high yields " with retention of configuration, e.g., heating a 1 1 cis-propenylboronic acid and Tl(III) chloride in aq ether for 8.5 h produces 30% cis-propenylthallium dichloride and 30% bis(cis-propenyl)thallium chloride. The same reaction with trans-propenylboronic acid produces 28% trans-propenylthallium dichloride and 67 % bis(trans-propenyl)thallium chloride. 

Divinyl ether itself presents a fairly complex case one detailed study claimed that the decomposition of the ether-phosphorus pentachloride complex with SO2 yields the phosphonic dichlorides 78-80 together with vinyl dichlorophosphate whilst a more recent study demonstrated that treatment of the intermediate complex with SO2 yielded 81, and with Asp3 yielded 82 in each case, a co-product was [2-(l-chloroethoxy)vinyl]phosphon-ic dichloride (78). The action of phosphorus pentachloride on the sulphide 83 presumably proceeds through 84, although in the work-up procedures thus far adopted, dehydrohalo-genation occurs to give 85 (R = Cl) ... 

Benzene, m-divinyl. See m-Divinylbenzene Benzene, dodecyl-1,3-bis (trimethylammoniomethyl)-, dichloride. See Dodecyixylyiditrimonium chloride Benzene, (epoxyethyl). See Styrene oxide Benzene, 1,1 -(1)2-ethanediyl) bis-. See Di benzyl... 

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