The syntheses of [3]- and [4]cyclo-9,9-dimethyl-2,7-fluorenes ([3] and [4]CFRs), cyclic trimer, and tetramers of 9,9-dimethyl-2,7-fluorene (FR), respectively, were achieved by the platinum-mediated assembly of FR units and subsequent reductive elimination of platinum. A triangle-shaped tris-platinum complex and a square-shaped tetra-platinum complex were obtained by changing the platinum ligand. The structure of the triangle complex was unambiguously determined by X-ray crystallographic analysis. Reductive elimination of each complex gave [3] and [4]CFRs. Two rotamers of [3]CFR were sufficiently stable at room temperature and were separated by chromatography. The physical properties of the CFRs were also investigated theoretically and experimentally.

Bromination of [n]cycloparaphenylenes (CPPs) is herein reported. Small [n]CPPs (n<8) underwent a bis-bromine addition reaction with high site selectively to produce tetrabromo adducts in moderate to excellent yields. Theoretical calculations revealed that thermodynamic stability dictates both the reactivity and site selectivity of the reaction. The addition product was further converted into the octabromo product by a FeBr -catalyzed site-selective bromination reaction. The tetra- and octabromine adducts were then transformed into mono- to tetrabromo CPPs, which were further converted into several CPP derivatives. Therefore, bromination and subsequent transformations provide a path for late-stage functionalization of CPPs.

Bromination of [n]cycloparaphenylenes (CPPs) is herein reported. Small [n]CPPs (n < 8) underwent ab isbromine addition reaction with high site selectively to produce tetrabromo adducts in moderate to excellent yields.Theoretical calculations revealed that thermodynamic stability dictates both the reactivity and site selectivity of the reaction. The addition product was further converted into the octabromo product by aF eBr 3 -catalyzed site-selective bromination reaction. The tetra-and octabromine adducts were then transformed into mono-to tetrabromo CPPs,w hich were further converted into several CPP derivatives.T herefore,b romination and subsequent transformations provideapath for latestage functionalization of CPPs.