Replacing the phenol in the propofol example (5, 91% conversion (88% isolated), with a similar but less sterically demanding methoxy example resulted in only trace conversion to the para-sulfonated 13 (by time course 1 H NMR spectroscopy). The need for an available hydroxyl group can be further ascribed from the results of 14. A range of conditions were applied (r.t to 85 °C) and solvents (DCM, MeCN, and 1,2-DCE) at best at ~10% conversion was found. Isolation of the sulfated furan was further complicated by the presence of residual TBSAB (23% w/w purity by 1 H NMR spectroscopy).