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酮转化氰基
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用TosMIC 直接从酮转化为氰基

      对甲苯磺酰甲基异氰(TosMIC) 是有机化学官能团转换反应中最有用的多功能试剂和合成子之一。TosMIC 在杂环合成中可以用来方便地制备咪唑、噻唑、 恶唑、三氮唑、吲哚、吡咯等。TosMIC 参与的增加一个碳原子的还原氰基化反应和二烷基化反应具有独到之处。

     TosMIC与酮生成腈的还原氰基化反应是该试剂最特征的反应之一。反应的机理是TosMIC在碱的存在下生成碳负离子与酮羰基发生亲核加成反应,然后失去磺酰基和甲酰基生成腈[2]。该反应需要使用过量的碱,常用的碱为t-BuOK。反应一般在室温下数小时内完成,产率中等到较高水平 (式1,式2)[3,4]。TosMIC与甾体17-酮反应时,生成两种异构体的混合产物 (式3)[5]。


  TosMIC 与卤代烃发生烷基化反应,生成多一节碳的酮[6,7]。分子间的烷基化反应生成对称或者不对称的链状酮,分子内的烷基化反应生成相应的环状酮 (式4,式5)[6,7]。

 

  TosMIC 与α,β-不饱和羰基化合物反应生成吡咯环的反应一般给出较好的产率,羰基或者其它拉电子基团的存在对反应活性的影响非常大 (式6,式7)[8,9]。最近有人报道简单的芳基乙烯就可以与TosMIC 发生形成吡咯环的反应 (式8)[10]。


 

酮转化为氰基示例

  To a 250 mL round-bottomed flask equipped with condenser and nitrogen inlet were added 4.34 g (23.49 mmol) N-carboethoxyperhydroazepin-4-one (prepared according to the procedure given by Z. G. Finney and T. N. Riley, J. Med. Chem., 23, 895, 1980), 10.53 g(54.02 mmol) tosylmethylisocyanide and 117 mL 1,2-dimethoxyethane. The solution was cooled to 0 deg C and 2.48 mL (54.02 mmol) ethanol and 9.21 g (82.2 mmol) potassium t-butoxide were added. The mixture was heated at 60 deg C for 18 hours, cooled and concentrated. The residue was taken up in ethyl acetate, washed with brine, dried over sodium sulfate and concentrated to give an oil. The oil was purified by chromatography on silica gel using hexane/ethyl acetate as eluent to afford 4.6 g (100percent) of oil.

用2,4,6- 三异丙基磺酰肼-KCN 将酮转化为氰基


3-Quinuclidinone (24.2 g, 0.19 mol) and 2,4,6-triisopropylbenzenesulphonohydrazide (72g, 0.24 mol) were stirred together in anhydrous MeOH (250 mL) for 3 h. Potassium cyanide (33.8 g, 0.51 mol) was added and the mixture was heated under reflux for 5 h. The residue after evaporation of the solvent was partitioned between water and CH2C12. The organic phase was dried and evaporated and the residue was fractionally distilled under reduced pressure to give 3-cyanoquinuclidine (32, 6.1 g).

 

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