Nacnac BnCuOiPr: a strained geometry resulting in very high lactide polymerization activity

N,N′-Dibenzyl diketiminate copper isopropanolate, (nacnacBnCuOiPr)2, polymerizes rac- and S,S-lactide in the presence or absence of isopropanol as a chain-transfer reagent with very high activity (k2 = 32 M−1 s−1), narrow polydispersities and without evidence of side reactions such as transesterification, epimerization or catalyst decomposition.