Stereoselective Synthesis of 1-Nitrobicyclo[3.1.0]hexanes and Fused Isoxazoline-<i>N</i>-oxides from Primary Nitro Compounds
作者:Akio Kamimura、Ryota Takeuchi、Kosuke Ikeda、Takaaki Moriyama、Michinori Sumimoto
DOI:10.1021/jo202489v
日期:2012.3.2
The one-step preparation of 1-nitrobicyclo[3.1.0]hexane and bicycloisoxazoline-N-oxide was readily achieved from conjugate adducts of nitro alkenes and allylmalonates by treatment with Ag2O and iodine under basic conditions. We observed that when a primary alkyl group was present at the β-position of the nitro group, bicyclo[3.1.0]hexane was preferentially formed, whereas if a secondary alkyl group
1-硝基双环[3.1.0]己烷和双环异恶唑啉-N-氧化物的一步制备很容易通过在碱性条件下用Ag 2 O和碘处理硝基烯烃和丙二酸烯丙酯的共轭加合物来实现。我们观察到,当硝基的β位上存在伯烷基时,优先形成双环[3.1.0]己烷,而如果仲烷基占据该位置,则主要生成异恶唑啉-N-氧化物。在两个反应中,对于环戊烷单元的形成都观察到高的顺式选择性。分离出碘代甲基加合物,将其视为环化的中间体,并将其转化为异恶唑啉-N氧化物成功实现。异恶唑啉-N-氧化物与烯烃进行1,3-偶极环加成反应生成三环杂环化合物,可通过使用阮内镍(Raney-Ni)对N–O键进行还原性裂解,将其容易地以良好的产率转化为螺内酰胺。另一方面,异恶唑啉-N-氧化物的1,3-偶极环加成至末端炔烃立体选择性地产生三环氮丙啶。