Vinylene Carbonate

Swern Oxidation of Bicyclo[2.2.1]hept-5-ene-2,3-diol and Its Pyrazine-fused Derivatives: An Improved Synthesis of Bicyclo[2.2.1]hept-5-ene-2,3-dione and An Unexpected Ring-Opening Reaction

“…Furthermore, we could not reproduce the reported yield of the Diels-Alder re-action of 1 with cyclopentadiene: the adduct 2 was obtained only in 40-50% yields whereas 65-70% yields were claimed in the literature [3]. Thus, we report here an improved synthesis of 1 starting from more readily available vinylene carbonate (4) [4]. Bicyclo[2.2.1]hept-5-ene-2,3-diol (6) was prepared by the Diels-Alder reaction of vinylene carbonate (4) and cyclopentadiene followed by the hydrolysis as described in the literature [5].…”

Synthesis of Substituted Hydrindanes. Part I. Products Arising from the Cyclization of Acetonyl Cyclohexanones and Acetonyl Cyclohexadiones

“…This was prepared by the method of Rosenmund (7) 2-Propargyl-2-(2-cyanoethyl) -5,5-dimethylcyclohexa-I ,3-dione (5a) To potassium (1.02 g) dissolved in t-butyl alcohol (50 ml) under nitrogen, is added cyanoethyldimedone 2a (4.8 g) followed by propargyl bromide (4.5 ml) dropwise and the mixture is refluxed for 15 h. After cooling and pouring into ice water, the propargyl derivative 5a crystallizes (4.7 g, 83%), m. 2-Acetonyl-2-(2-cyanoethyl) -5,5-dimethylcyclohexa-I ,3-dione (6a) To the propargyl derivative 5a (4 g) in methanol (150 ml) and ethoxyethanol (5 ml) is added aqueous sulfuric acid (0.3 ml of 1 N) and Dowex 50W-X4 resin (0.9 g) charged with mercuric ions (8 NOTE: Owing to a certain loss of activity of the treated resin on standing, this hydration is more reproducible using the boron trifluoride -trichloroacetic acid method described later (see 10c).…”

The Chlorination of the Olefins

“…Ethylene carbonate can be chlorinated in the light. The resulting monochloro product can be dehydrochlorinated with triethanolainine to give vinylene carbonate [252]. This can be polymerized [253].…”