The organocatalytic ring-opening of N-tosyl protected aziridines by beta-ketoesters under chiral PTC-conditions, leading to the formation of optically active aminoethyl functionalised compounds with up to 99% ee, has been developed.

Alcohol is the answer! An inactive, air-stable, dimeric molybdenum alkylidyne complex is activated toward ring-opening alkyne metathesis polymerization (ROAMP) by the addition of methanol. The ROAMP is compatible with water and phenol-containing substrates and with the in situ photochemical generation of alkyne monomers from cyclopropenones.

The need for polymers for high-end applications, coupled with the desire to mimic nature's macromolecular machinery fuels the development of innovative synthetic strategies every year. The recently acquired macromolecular-synthetic tools increase the precision and enable the synthesis of polymers with high control and low dispersity. However, regardless of the specificity, the polymerization be...

Donor-acceptor cyclopropanes with two geminal carboxylic esters are reacted with chalcogenyl chlorides and bromides to afford ring-opened products bearing the halogen atoms in the 1-position, adjacent to the donor, and the chalcogenyl residue in the 3-position next to the two acceptor groups. A variety of different donors (e.g., aryl, N, and O) are used. The stereospecificity of the reaction is...

Cyclic monomers that have been polymerized via ring opening encompass a variety of structures, such as alkanes, alkenes, compounds containing heteroatoms in the ring: oxygen [ethers, acetals, esters (lactones, lactides, and carbonates), and anhydrides], sulfur (polysulfur, sulfi des and polysulfi des), nitrogen [amines, amides (lactames), imides, N carboxyanhydrides and 1,3 oxaza derivatives], ...

In living ring-opening metathesis polymerization (ROMP), a transition-metal-carbene complex polymerizes ring-strained olefins with very good control of the molecular weight of the resulting polymers. Because one molecule of the initiator is required for each polymer chain, however, this type of polymerization is expensive for widespread use. We have now designed a chain-transfer agent (CTA) cap...

MOD patterns are distorted by expansion of the investment during setting in the casting ring. Using a simple idealized epoxy resin MOD pattern and two-dimensional photoelasticity, this investigation reports the distortion under several conditions, including W/P ratios, cases with and without asbestos lining, number of asbestos layers, condition of the asbestos lining (dry, wet, and applied sili...

Ring opening of 1-arylmethyl-2-(cyanomethyl)aziridines with HBr afforded 3-(arylmethyl)amino-4-bromobutyronitriles via regiospecific ring opening at the unsubstituted aziridine carbon. Previous experimental and theoretical reports show treatment of the same compounds with benzyl bromide to furnish 4-amino-3-bromobutanenitriles through ring opening at the substituted aziridine carbon. To gain in...

This article summarizes and reviews recent progress in the development of catalysts for the ring-opening copolymerization of carbon dioxide and epoxides. The copolymerization is an interesting method to add value to carbon dioxide, including from waste sources, and to reduce pollution associated with commodity polymer manufacture. The selection of the catalyst is of critical importance to contr...

Despite the tremendous impact of alkene ring-opening metathesis polymerization (ROMP) on the design and the synthesis of polymers and functional materials, examples for the analogous alkyne ROMP remain scarce. This imbalance can be rationalized by the limited availability of commercially available catalysts and the lack of alkyne metathesis monomers. We present here the synthesis and a systemat...