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Please login or sign up for a free trial to access the full content. Oxidation To Afford Lactones and Aldehydes

DOI: 10.1055/sos-SD-203-00294

Andrus, M. B.Science of Synthesis: Stereoselective Synthesis, (20113480.

Various metal catalysts based on bismuth,[‌51‌] chromium,[‌52‌] rhodium,[‌53‌] iron,[‌54‌] and ruthenium,[‌55‌] in conjunction with tert-butyl hydroperoxide, have been employed to convert alkylbenzene derivatives into the corresponding carbonyl-containing aryl species. For example, catalytic bismuth(0), picolinic acid (pyridine-2-carboxylic acid), and tert-butyl hydroperoxide have been used in a convenient, regioselective oxidation of a benzopyran at the benzyl ether position to give the benzopyranone 20 in high yield (Scheme 7).[‌51‌] A series of versatile oxidation methods that utilize 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (2-iodylbenzoic acid, IBX) have also been reported. In particular, the oxidation of sensitive 1-(allyloxy)-2-methylbenzene with excess 2-iodylbenzoic acid in hot dimethyl sulfoxide selectively generates 2-(allyloxy)benzaldehyde (21) in very good yield (Scheme 7).[‌56‌]

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