Synthesis of polymethyl substituted [2.2]metaparacyclophanes and their Lewis-acid induced isomerisation to [2.2]metacyclophanes

The preparation of polymethyl substituted [2.2]metaparacyclophanes using sulfur method and the X-ray structure determination of 4,5,6,8,12,13,15,16-octamethyl[2.2]metaparacyclophane are described. AlCl3-MeNO2-catalysed trans-tert-butylation of 5-tert-butyl-8,12,13,15,16-pentamethyl[2.2]metaparacyclophane in benzene led to isomerisation reaction to afford the strainless 8,12,13,14,16-pentamethyl[2.2]metacyclophane in 85% yield along with tert-butylbenzene.