Synthesis and reactions of alkenyl-gem-dichlorocyclopropanes obtained from piperylene

Objectives. This study aims to obtain alkenyl-gem-dichlorocyclopropanes from piperylene. The products are then subjected to thermocatalytic isomerization and hydrogenation. Methods. To determine the qualitative and quantitative composition of the reaction crudes, the following analytical methods were used: gas-liquid chromatography using the Crystal 2000 hardware complex, mass spectrometry using a Chromatec-Crystal 5000M device with the NIST 2012 database, and nuclear magnetic resonance (NMR) spectroscopy using a Bruker AM-500 device at operating frequencies of 500 and 125 MHz. Results. Alkenyl-gem-dichlorocyclopropanes were synthesized in the presence of triethylbenzyl ammonium chloride as catalyst. Their isomerization and hydrogenation gave the corresponding gem-dichlorocyclopentene and isomers of alkyl-gem-dichlorocyclopropanes. The structure of synthesized substances were analyzed by gas-liquid chromatography, mass spectrometry, and NMR spectroscopy. Conclusions. The results show that formation of four isomeric substituted gemdichlorocyclopropanes occurs in high yield during incomplete dichlorocyclopropanation of piperylene. The thermocatalytic isomerization of substituted gem-dichlorocyclopropanes in the presence of SAPO-34 zeolite leads to the formation of one product, i.e., gem-dichlorocyclopentene, and hydrogenation of substituted gem-dichlorocyclopropanes in the presence of Pd/C catalyst gives three isomeric alkyl-gem-dichlorocyclopropanes.