Synthesis of cobalt-containing cyclophanes,and the formation of an unprecedented seven-membered cyclic diyne

摘要

The acid-catalysed Nicholas reaction of the bis-propargyl complex [{Co_2(CO)_6(mu-eta~2-HOMe_2CC implied by C-)}_2] 1 in the presence of a variety of nucleophiles leads in each case to [{Co_2(CO)_6}_2{cyclo-mu-eta~2:mu-eta~2-C(=CH_2)CH_2CMe_2Cimplied by C-C implied by C}],a complex which contains an unprecedented seven-membered macrocyclic diyne ligand.The reactivity of 1 is compared to that of [{Co_2(CO)_6}_2{(mu-eta~2:mu-eta~2-l,4-C_6H_4(C implied by CCMe_2OH)_2}] which does not cyclise on treatment with nucleophiles but instead gives the expected substitution products.