Block copolymerization of a seven-membered cyclic carbonate (5S,6S)-dimethyl-5,6-isopropylidene1,3-dioxepin-2-one (ITC) with epsilon-caprolactone in "one-shot feeding" is reported. The cyclic carbonate monomer ITC was synthesized from naturally occurring L-tartaric acid in three steps. Three catalysts-stannous octanoate, Sn(Oct)(2), triisopropoxide aluminum, Al((OPr)-Pr-i)(3), and diethylzinc monohydrate, ZnEt2-H2O-were tested for the homopolymerization of ITC monomer at 120 degrees C for 12 h in bulk. The results show that Sn(Oct)(2) was the most effective catalyst to carry out the polymerization (M-n = 24000 g/mol; PDI = 1.6; [alpha](D)(20) = +77.8). The copolymerization of ITC with E-caprolactone (CL) in various feed ratios was also investigated. The detailed spectral and thermal analysis of the copolymers catalyzed by Sn(Oct)(2) revealed formation of the block copolymer (poly [44%ITC-block-56%CL], M-n = 24000 g/mol; PDI = 1.6; [alpha](D)(20) = +33.8). Two glass transition temperatures (T-g) were observed for poly(44%ITC)-block-poly(56% epsilon-CL) at -59.1 and -37.2 degrees C for the poly(CL) and the poly(ITC) block, respectively, confirming the diblock nature of the copolymer. It is the first report of "one-shot" block copolymerization of E-caprolactone with a cyclic carbonate monomer. The deprotection of the ketal groups resulted in copolymers containing free hydroxy groups in the polymer backbone.