Synthesis of methano-bridged tetradehydrodiaza[22]annulene and related compounds

Abstract

Synthesis of 9,22-diethoxy-13,18-dimethyl-14,15,16,17-tetradehydro-2,7-methano-1,8-diaza[22]annulene (9,22-diethoxy-13,18-dimethyl-2.7-methano-1,8-diazacyclodocosa-2,4,6,8,10,12,18,20,22-nonaene-14,16-diyne), is described. Examination of ¹H NMR and electronic spectra indicates that the diaza[22]annulene shows no ring current effect but does show polyolefinic character despite the potential diatropic 22π-electron system. Attempts to prepare the higher analogues, diaza[24]- and -[26]annulenes are also described.