Bart A. J. Noordover, Daniël Haveman, Robbert Duchateau, Rolf A. T. M. van Benthem and Cor E. Koning
Scheme S1 The formation of a methyl ether end-group through the reaction between a pyridinium complex and methanol during the precipitation of the concentrated polymerization reaction mixture in methanol.
Figure S2 carbonyl source.
1 H NMR spectrum of poly(isoidide carbonate), polymer 3 , prepared using TPh as a

Figure S3 Sections of MALDI-ToF-MS spectra of polycarbonates 1 , 3 and 5 , with ( A ) linear chains with two hydroxyl end-groups, ( B ) cyclic chains and ( H ) linear chains containing one ether linkage and having methyl carbonate or ether end-groups. Codes refer to structures drawn in Scheme
3.

Figure S4 1 H NMR spectrum of polycarbonate 4 , poly(isoidide carbonate), where R can be a proton, a carbonic phenyl ester or the other end of the same polycarbonate chain, forming a cyclic chain.
Figure S5 Sections of the MALDI-ToF-MS spectra of polycarbonates 2 , 4 and 6 (Table 1).
Species: ( A ) linear chains, two hydroxyl end-groups; ( B ) cyclic chains; ( K ) linear chains, one hydroxyl and one phenyl carbonate end-group; ( M ) linear chains, two phenyl carbonate end-groups.

Figure S6 Fragment of the MALDI-ToF-MS spectrum of poly(isosorbideco -propylene carbonate) 13 , showing peaks corresponding to the following species: ( A ) linear chains with two hydroxyl end-groups; ( B ) cyclic chains; ( K ) linear chains having one hydroxyl and one phenyl carbonate end-group; ( L ) linear chains containing an ether linkage and having one hydroxyl and one phenyl carbonate end-group.
Figure S7 1 H NMR spectrum of isoidide bis(phenyl carbonate), recorded in chloroformd .

Figure S8 linear chains, two hydroxyl end-groups; ( B ) cyclic chains.
Section of the MALDI-ToF-MS spectrum of polycarbonate 19 (Table 4). Species: ( A )
Scheme S9 Curing agents used to prepare poly(carbonate urethane) coatings.