Towards a hexa-branched [7]rotaxane from a [3]rotaxane via a [2+2+2] alkyne cyclotrimerization process.

A facile synthesis methodology to obtain a crown ether-based hexa-branched [7]rotaxane, has been achieved by using Co-catalyzed [2+2+2] alkyne cyclotrimerization from a [3]rotaxane. The [2+2+2] alkyne cyclotrimerization process, which requires only 10 mol% of Co2(CO)8 as a catalyst and affords an efficient production of target rotaxanes, represents a new strategy for the construction of highly complicated dendritic rotaxanes. [ABSTRACT FROM AUTHOR]