Polyethylene glycol (PEG) has proven to be a versatile soluble-polymer supp
ort for organic synthesis, though the use of PEG has been limited by its re
latively low loading (0.5 mmol/g or less). We have developed a new high-loa
ding (1 mmol/g) soluble-star polymer based on a cyclotriphosphazene core wi
th PEG arms that exhibit superior precipitation properties compared with th
ose of linear PEG. Additionally, the heterocyclic core does not add interfe
ring signals to the H-1 or C-13 NMR.