Three new families of macrocyclic olefins were prepared from deoxycholic acid. Two of these have a novel structure in that the bile acid unit is linked to a C20 fatty acid unit via the 3α- and 12α-positions, thus creating macrocycles with rings with a repeat unit of 29 ring atoms. Entropically-driven ring-opening methathesis polymerizations (ED-ROMPs) of the macrocycles gives polymers with free hydroxyl groups, or free methyl or t-butyl carboxylic ester groups. The latter could be converted into carboxylic acid groups by treatment with trifluoroacetic acid. The polymers form transparent hole-free films that are potentially useful for supporting cell growth.

Various macrocyclic lactones containing bile acid residues successfully undergo entropically-driven ring-opening polymerization via transesterifications (TEs) catalyzed by polymer-supported Candida antarctica lipase B (PS-CALB) when the 3α- and 24-positions are linked by C14 or C20 chains or by a 23-atom chain, but not when the 3α- and 12α-positions are linked by a C20 chain. This suggests that the α-face of the bile acid derivatives in the region of the A–C rings sit at the active site of the enzyme. TEs of model bile acid derivatives indicate that the order of reactivity of ester groups catalyzed by CALB is 3α-OAc > 26-OAc ≫ 24-CO2R, though the latter do react. The 12α-OH does not react. Accordingly, under the polymerization conditions used in this work, the polymeric products formed from the macrocyclic bile acid derivatives containing a C14 or C20 linkage between the 3α- and 24-positions are expected to be a polymer chain formed essentially by ring-opening at the 3α-position, with the repeat units arranged in a regular head-to-tail manner. This differs from the structure of the polymers obtained by ED-ROMP of the same macrocycles. The macrocycles formed formally from glycol lithocholate (the diol unit) and E/Z-eicos-10-enedioic acid (the diacid unit) afford polymers that essentially have these units linked in an alternating manner. There are regiosiomers because of the unsymmetrical diol unit. Esterifications and TEs catalyzed by PS-CALB using a large excess of appropriate volatile aliphatic esters are a useful alternative to more expensive activated esters in the synthesis of esters using PS-CALB.

Macrocyclic oligomers (MCOs) are important as starting materials for Entropically-driven Ring-opening Polymerizations (ED-ROPs). This article reviews the preparation of MCOs by the cyclodepolymerization (CDP) of condensation polymers. Many MCOs have been prepared successfully this way and in numerous cases individual macrocycles have been isolated. This approach can provide one-step syntheses of many macrocycles. The combination of CDP plus ED-ROP is an attractive potential method for recycling (‘Ring-chain Recycling’) many condensation polymers.

A new type of traceless linker is described for use in polymer-supported (PS) syntheses of thiophene-containing compounds. It is based on the cleavage of PS aryl 2-thienyl ketones by a mixture of potassium t-butoxide and water (typical mol ratio 10:3) in an ethereal solvent. Cleavage occurs to give the soluble thiophene-containing product. The method is used to prepare a range of eight thiophene-containing compounds including a terthiophene and a dialkylquaterthiophene. PS unsymmetrical diaryl ketones incorporating, for example, ortho-methoxyphenyl or pyrrole moieties could also serve as traceless linkers.

Macrocyclic esters with 24- to 84-ring atoms can be polymerized successfully using PS Candida antarctica lipase B as the catalyst. This method allows the polymerization of macrocycles containing substantial in-chain functional moieties, such as monomers incorporating steroid residues. It also affords metal-free products.

In this work we present some experimental evidence of the existence of carbonyl–π electron cloud interactions. Such interactions are analogous to anion–π interactions, which have been predicted to be energetically favourable in the case of electron deficient aromatic rings. UV-Visible spectroscopy and cyclic voltammetry results obtained for 9,10-anthraquinone, 1,1′-bis-9,10-anthraquinone, poly(9,10-anthraquinone-1,4-diyl) and other 1,4-diaryl substituted anthraquinone derivatives are described. It was found that the steric hindrance occurring between the carbonyl groups and the adjacent aromatic substituent forces the plane of the anthraquinone moiety and that of the aromatic substituent to adopt a nearly orthogonal conformation, resulting in relatively strong carbonyl–π interactions that affect both the UV-Vis absorption spectrum and the reduction potential of the compound. Moreover, in the case of thiophene substituted derivatives, the torsion angle between the anthraquinone moiety and its aromatic substituent is smaller and therefore carbonyl–π interaction effects are not observed in these compounds.

A new type of traceless linker is described for use in polymer-supported (PS) syntheses of thiophene-containing compounds. It is based on the cleavage of PS aryl 2-thienyl ketones by a mixture of potassium t-butoxide and water (typical mol ratio 10:3) in an ethereal solvent. Cleavage occurs to give the soluble thiophene-containing product. The method is used to prepare a range of eight thiophene-containing compounds including a terthiophene and a dialkylquaterthiophene. PS unsymmetrical diaryl ketones incorporating, for example, ortho-methoxyphenyl or pyrrole moieties could also serve as traceless linkers.