Search for carbon-carbon bond formation by the use of boranonitrone

用BF_3·OE_T2保护的肟制得的硼硝酮与烯烃发生分子间环加成反应，以较高的产率合成了相应的异恶唑烷。有趣的是，N-硼基-C-乙氧基甲基硝酮与烯烃的环加成反应生成了3，5-反式异恶唑烷，而叔丁基二甲基硅氧亚胺-N，N-二甲基乙基酰胺与烯烃反应生成了3，5-顺式异恶唑烷。该反应对N-O键的还原断裂合成1，3-反和1，3-合成氨基醇是非常有用的。此外，N-硼基-C-乙氧羰基硝酮与碳自由基物种反应生成了相应的羟胺，产率较高。

Boranonitrone, generated from protected oxime with BF_3.OE_t2, underwent intermolecular cycloaddition with alkenes to afford the corresponding isoxazolidines in good yields. Interestingly, the cycloaddition of N-borano-C-ethoxycarbonyl nitrone with alkenes gave 3,5-trans-isoxazolidines, whereas the reaction of tent-butyldimethylsilyloximino-N,N-dimethylethane-amide with alkenes afforded 3,5-cis-isoxazolidines. This reaction is very useful for synthesis of 1,3-anti and 1,3-syn aminoalcohols by reductive cleavage of an N-O bond. Additionally, the reaction of N-borano-C-ethoxycarbonyl nitrone with carbon radical species afforded the corresponding hydroxylamines in good yields.