Isoselective lactide ring opening polymerisation using [2]rotaxane catalysts

Polylactide (PLA) is a fully biodegradable and recyclable plastic, produced from a bio‐derived monomer: it is a circular economy plastic. Its properties depend upon its stereochemistry and isotactic PLA shows superior thermal‐mechanical performances. Here, a new means to control tacticity by exploiting rotaxane conformational dynamism is described. Dynamic achiral [2]rotaxanes can show high isoselectivity (Pi=0.8, 298 K) without requiring any chiral additives and enchain by a chain end control mechanism. The organocatalytic dynamic stereoselectivity is likely applicable to other small‐molecule and polymerization catalyses.