A one pot method of preparing cyclic carbonyl compounds comprising an active pendant pentafluorophenyl carbonate group is disclosed. The cyclic carbonyl compounds can be polymerized by ring opening methods to form ROP polymers comprising repeat units comprising a side chain pentafluorophenyl carbonate group. Using a suitable nucleophile, the pendant pentafluorophenyl carbonate group can be selectively transformed into a variety of other functional groups before or after the ring opening polymerization.