Thermolysis of trifluoromethyl-containing vinyldiazocarbonyl compounds and X-ray crystal structure analysis of unexpected reaction products

Two unusual compounds, 1,3a,6,6a-tetrahydro-3a,6a-bis(trifluoromethyl)-cyclopenta[c]pyrazol-3,4,5,6-tetracarboxylic acid tetramethyl ester (C16H14N2O8F6) (3) and 2-acetyl-5,7-bis(trifluoromethyl)-4-methyl-3-methoxy-2,4,6-cycloheptatrienecarboxylic acid methyl ester (C14H11F6O3) (4), were obtained from thermolysis of 3-trifluoromethyl-substituted vinyldiazocarbonyl compounds. The crystal structures of the products were determined as part of a larger comparison study on the thermal and Rh(II)-catalyzed reactions of F- and H-vinyldiazocarbonyl compounds. The resulting structures provide the first crystallographic characterization of bis(trifluoromethyl)substituted compounds of this kind. The pure compounds with all-carbon (4) and half-heterocyclic (3) skeletons are composed of a seven- and two-annulated five-membered rings in folded butterfly and envelope conformations, respectively.