Cyclophanes in which two cyclic conjugated n-systems face each other are ideal models for studying the interactions of two n-systems as a function of distance and intervening (~-skeleton. 1~ For this reason a simple access to these systems is desirable. We here report a one-pot synthesis of cyclophanes consisting of one CpCo-capped cyclobutadiene system and one CpCo-capped cyclopentadienone system which are connected by four pentamethylene and four heptamethyiene chains, respectively. The motivation for this study goes back to our recent report on the stepwise synthesis of 4 from 5-cyclodecynone (1) and dicarbonyl(qLcyclopentadienyl)cobalt (CpCo(CO)2) as summarized in Scheme 1.4 Scheme 1 1 CpCo(CO) 2 Decalin, 190 *C, 5 d " 0 lele Cp Co CpC°(CO)2 . Decalin, 190 *C O Co Cp 3 4
In order to obtain congeners of 4 in which the n-systems are further apart we went back to earlier investigations s which revealed a one-pot synthesis of CpCo-capped cyclobutadiene-superphanes, when heating 1,6-cyclodecadiyne e, 1,8-cyclotetradecadiyne (5),7 and 1,10-cyclooctadecadiyne (6) with CpCo(CO)2. 8 Heating of 5 and 6 with CpCo(CO)2 at 140 °C in xylene for five days afforded the superphanes 79 and 89, respectively, in 5 % yield (s. Scheme 2)