O-tert-propargylic oximes derived from tertiary propargylic alcohols was established via Nicholas reaction. Thus, BF3·OEt2-mediated reaction between the dicobalt hexacarbonyl complex of tert-propargylic alcohols and p-nitrobenzaldoxime followed by decomplexation with cerium(IV) ammonium nitrate afforded the corresponding O-tert-propargylic oximes in good to high yields. The obtained O-tert-propargylic oximes were
radicals has been accomplished under oxidant-free conditions. This approach offers a mild, atom-economical, and redox-neutral synthesis of 5-methylisoxazolines through radical hydroxygenation of β,γ-unsaturatedoximes in the absence of an additional hydrogen source.
Cobalt complex Co(nmp)2 can efficiently catalyze the aerobic oxidative 5-exo cyclization of β,γ-unsaturatedoximes to afford isoxazolines. The key cyclization step involves the generation of carbon-centred radicals. The products are largely dependent on the reaction conditions. The oxidative termination products 2 were produced predominantly when the reaction was carried out in i-PrOH, whereas the
A method for aliphatic C-H bond oxidation of oximes and hydrazones mediated by 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) has been developed, which enables the concise assembly of substituted isoxazole and pyrazole skeletons.