Repositori URV

Identifier: imarina:9262313

Handle: https://hdl.handle.net/20.500.11797/imarina9262313

Authors:
Qiao CShi WBrandolese ABenet-Buchholz JEscudero-Adán ECKleij AW

Abstract:
A new catalytic route has been developed for the coupling of epoxides and CO2 affording polymerizable six-membered bicyclic carbonates. Cyclic epoxides equipped with a beta-positioned OH group can be transformed into structurally diverse bicyclic cyclic carbonates in good yields and with high selectivity. Key to the chemo-selectivity is the difference between the reactivity of syn- and anti-configured epoxy alcohols, with the latter leading to six-membered ring carbonate formation in the presence of a binary Al-III aminotriphenolate complex/DIPEA catalyst. X-ray analyses show that the conversion of the syn-configured substrate evolves via a standard double inversion pathway providing a five-membered carbonate product, whereas the anti-isomer allows for activation of the oxirane unit of the substrate opposite to the pendent alcohol. The potential use of these bicyclic products is shown in ring-opening polymerization offering access to rigid polycarbonates with improved thermal resistance.