VINYLENE CARBONATE Sir: We wish to report the synthesis of vinylene car- bonate, 111, by the dehydrochlorination of chloro- ethylene carbonate, 11, formed by the chlorination of ethylene carbonate, I. We believe 111 to be the first example of a cyclic carbonate of an enediol. ... Vinylene carbonate reacts with 2,3-dimethyl- butadiene to form a crystalline adduct, the cyclic carbonate of cis-4,5-dihydroxy-l,2-dimethylcyclo- hexene and is catalytically reduced to ethylene ...