Science of Synthesis

Dornan, L. M.; Hughes, N. L.; Muldoon, M. J., Science of Synthesis: Catalytic Oxidation in Organic Synthesis, (2017) 1, 556.

2,2,6,6-Tetramethylpiperidin-1-oxyl (TEMPO, ‌5‌)/(diacetoxyiodo)benzene/water has previously been used as a method for preparing carboxylic acids from alcohols. Iwabuchi has reported that 1-methyl-2-azaadamantan-N-oxyl (1-Me-AZADO, ‌1‌) delivers superior chemoselectivity compared to TEMPO,[‌50‌] and (diacetoxyiodo)benzene and unhindered radicals have been used to prepare carboxylic acids as a key step in a total synthesis; examples include indolosesquiterpenoids,[‌51‌] (−)-kaitocephalin,[‌52‌] and yakuʼamide A.[‌53‌] The fact that many such target molecules contain alkene functionality is perhaps the reason that (diacetoxyiodo)benzene is often the oxidant of choice.

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References