To investigate the activity of TEMPO-polyCAT as a heterogeneous catalyst for alcohol oxidation, a solution of 3-phenyl-1-propanol (1, 1.0 equiv) and diacetoxyiodobenzene (1.2 equiv) in CDCl3 (0.1 M) with tetrakis(trimethylsilyl)silane as an internal standard was added to a 1 mL reaction solution containing a 200 mg TEMPO-polyCAT gel (0.02 mmol TEMPO-CL, 10 mol % relative to 3-phenyl-1-propanol) (Fig. ). >95% conversion of 1 to the corresponding aldehyde 2 was observed within 12 h. Moreover, the extent of conversion as a function of time was nearly identical to a homogeneous reaction using the same loading of TEMPO-CL as the catalyst. To ensure catalyst leaching was not responsible for the observed catalytic activity of TEMPO-polyCAT, the same reaction was run using the supernatant collected after washing a freshly prepared TEMPO-polyCAT sample four times with chloroform; conversion was <3% after 24 h. Additionally, the activity of the supernatant at the end of the catalytic reaction was tested: TEMPO-polyCAT was removed from the mixture and an additional portion of 1 and oxidant were introduced to the solution. After 10 h, less than 5% of the new substrate was converted to 2.