Synthesis of [n]- and [n.n]cyclophanes by using Suzuki-Miyaura coupling

Reaction of the bis-9-BBN adduct of several dienes with 1,3-dibromobenzene via Suzuki coupling leads to a series of n]metacyclophanes ranging in size from 10 to 17 atom members. In each case, two carbon-carbon bonds are formed in one reaction vessel. However, when the bis-9-BBN adduct of 1,5-hexadiene is coupled with a variety of aryl dihalides, larger n.n]cyclophanes were formed in preference to the n]cyclophanes. Four carbon-carbon bonds are formed in this instance. Single-crystal X-ray analyses of these n.n]cyclophanes reveal interestingly shaped molecules with large cavities.