Ring-opening polymerization

Ring-opening polymerization is defined by IUPAC (Penczek, S., Moad, G. (2008). Glossary of the terms related to kinetics, thermodynamics, and mechanisms of polymerization. (IUPAC Recommendations 2008), Pure and Applied Chemistry, 80(10), 2163–2193) as (cit.) “Ring-opening polymerization (ROP): Polymerization in which a cyclic monomer yields a monomeric unit that is either acyclic or contains fewer rings than the cyclic monomer”. The large part of the resulting polymerizations is living/controlled; practically all belong to chain polymerizations. After the introduction, providing basic information on chain polymerizations, the paper presents the concise overview of major classes of monomers used in ROP, including cyclic ethers, esters, carbonates, and siloxanes as well as cyclic nitrogen, phosphorus, and sulfur containing monomers. There are discussed also thermodynamics, kinetic polymerizability, and major mechanisms of ROP. Special attention is concentrated on polymers prepared by ROP on industrial scale.

Synthesis of the Common Monomeric Unit of Uroleuconaphins and Viridaphins via Hauser–Kraus Annulation

A stereoselective synthesis of a pyranonaphthoquinone derivative found in aromatic polyketide-derived aphid pigments is reported herein. This approach features the anionic [4+2]-annulation of phthalides with a carbohydrate-derived optically active enone. Additional synthetic steps provide access to the monomer fragment of uroleuconaphins and viridaphins. The optimizations for a facile preparation of phthalides bearing sulfonyl or cyano groups are also studied.