A hitherto unknown palladium-catalyzed reaction of nitroalkanes with hydroxy allylic acetates is reported. The reaction led to the formation of γ-nitrocarbonyl compounds instead of the usual unsaturated nitroalcohol expected upon displacement of the allylic acetate group.A hitherto unknown palladium-catalyzed reaction of nitroalkanes with hydroxy allylic acetates is reported. The reaction led to the formation of γ-nitrocarbonyl compounds instead of the usual unsaturated nitroalcohol expected upon displacement of the allylic acetate group.

Highly crystalline directional poly(ε-caprolactone) based on a tetrahydroxymethyl resorcin[4]arene initiator core was synthesized by a “core first” method viaring-opening polymerization catalyzed by Sn(Oct)2 in bulk at 120 °C.

Block copolymerization of a seven-membered cyclic carbonate (5S,6S)-dimethyl-5,6-isopropylidene-1,3-dioxepin-2-one (ITC) with ε-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(OiPr)3, and diethylzinc monohydrate, ZnEt2−H2O—were tested for the homopolymerization of ITC monomer at 120 °C for 12 h in bulk. The results show that Sn(Oct)2 was the most effective catalyst to carry out the polymerization (Mn = 24 000 g/mol; PDI = 1.6; [α]D20 = +77.8). The copolymerization of ITC with ε-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], Mn = 24 000 g/mol; PDI = 1.6; [α]D20 = +33.8). Two glass transition temperatures (Tg) were observed for poly(44%ITC)-block-poly(56% ε-CL) at −59.1 and −37.2 °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 ε-caprolactone with a cyclic carbonate monomer. The deprotection of the ketal groups resulted in copolymers containing free hydroxy groups in the polymer backbone.

Enantiomerically pure functional polycarbonate was synthesized from a novel seven-membered cyclic carbonate monomer derived from naturally occurring l-tartaric acid. The monomer was synthesized in three steps and screened for polymerization with four commercially available lipases from different sources at 80 °C, in bulk. The ring-opening polymerization (ROP) was affected by the source of the enzyme; the highest number-average molecular weight, Mn = 15500 g/mol (PDI = 1.7; [α]D20 = +77.8, Tm = 58.8 °C) optically active polycarbonate was obtained with lipase Novozyme-435. The relationship between monomer conversion, reaction time, molecular weight, and molecular weight distribution were investigated for Novozyme-435 catalyzed ROP. Deprotection of the ketal groups was achieved with minimal polymer chain cleavage (Mn = 10000 g/mol, PDI = 2.0) and resulted in optically pure polycarbonate ([α]D20 = +56) bearing hydroxy functional groups. Deprotected poly(ITC) shows Tm of 60.2 °C and ΔHf = 69.56 J/g and similar to that of the poly(ITC), a glass transition temperature was not found. The availability of the pendant hydroxyl group is expected to enhance the biodegradability of the polymer and serves in a variety of potential biomedical applications such as polymeric drug delivery systems.

The synthesis and X-ray crystal structures of the first resorcin[4]arene cavitands by ring-closing metathesis reaction are described.

Novel octaester cavitands show intramolecular inclusion of ester moieties within the cavitand cavity.

The synthesis and X-ray crystal structures of the first resorcin[4]arene cavitands by ring-closing metathesis reaction are described.

Highly crystalline directional poly(ε-caprolactone) based on a tetrahydroxymethyl resorcin[4]arene initiator core was synthesized by a “core first” method viaring-opening polymerization catalyzed by Sn(Oct)2 in bulk at 120 °C.