Synthesis of Functionally Substituted Bicyclo[4.2.1]nona-2,4-dienes and Bicyclo[4.2.1]nona-2,4,7-trienes by Cobalt(I)-catalyzed [6π + 2π] Cycloaddition of 2‑Tropylcyclohexanone

The [6π + 2π] cycloaddition of 2-tropylcyclohexanone to allenes and alkynes was accomplished for the first time using the three-component catalytic system Co­(acac)2(dppe)/Zn/ZnI2, thus giving previously unknown functionally substituted bicyclo[4.2.1]­nona-2,4-dienes and bicyclo[4.2.1]­nona-2,4,7-trienes in high yields (70–89%). The structures of the synthesized carbocycles were reliably proved using modern spectral methods and X-ray diffraction. The in vitro cytotoxic activity of the obtained bicyclo[4.2.1]­nona-2,4-dienes and bicyclo[4.2.1]­nona-2,4,7-trienes against the Jurkat, K562, and U937 tumor cell lines has been studied.