Controlled “one-pot” block copolymerization of β-butyrolactone and oxiranes via quantitative active centers transformation

•Quantitative conversion of alkoxylate to carboxylate active centers was developed.•Linear block copolymers of oxirane (EG and glycidol) and β-BL were synthesized.•The conversion is quantitative for primary and secondary alkoxylates.•The impact of the presence of hydroxyl groups in polymerization of β-BL was studied.•Branched copolymer of glycidol and β-BL can be synthesized by developed method.