| Abstract
| - The radical hydroxylation of B-alkylcatecholboranes, easily prepared by hydroboration of olefins,has been investigated. When molecular oxygen was used as oxidizing agent, the correspondingalcohols were obtained directly without alkaline treatment. The presence of Lewis base additivessuch as Et3N or DABCO has a benefic effect on the selectivity and yield. Alternatively, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) reacts cleanly with B-alkylcatecholboranes to afford alkylradicals that can be trapped by a second equivalent of TEMPO to give alkoxyamines. Reduction ofthe alkoxyamines with zinc in acetic acid affords the desired alcohols. The whole procedure isparticularly mild and does not require any basic condition. The two approaches presented in thispaper are valuable and represent mild alternatives to the classical alkaline oxidation of organoboranes to alcohols.
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