硝基环烯类MBH酯——2-硝基-2-环己烯醇乙酸酯的合成研究

Study on the synthesis of 2-nitrocyclohex-2-enyl acetate,a compound from the nitro-cyclic olefin MBH ester family

2-硝基-2-环己烯醇乙酸酯是双Michael加成反应受体,能够进行两次串联或级联的Michael加成反应,形成2个新的碳-碳键或碳-杂原子键,同时构建3个手性中心,是高效合成多环杂环,特别是多环生物碱类化合物的重要中间体.现有合成方法存在试剂不环保、产率不高等缺点.文章以戊二醛和硝基甲烷为原料,经双Henry反应、乙酰化反应和消除反应制备目标化合物,3步反应总产率为86%,批产量可达20 g以上.合成方法原料廉价易得,反应条件温和,后处理简单,为硝基环烯类MBH乙酸酯提供了一个高效简洁的合成方法.

2-nitro-2-cyclohexenol is one of the receptors participating in the double Michael addition reaction.It＇s able to create two new C-C bonds（ or C-heteroatom bonds） and construct three chiral centers by participating twice in the tandem or cascade double Michael addition reactions.These advantages make it become a crucial intermediate in the efficient synthesis of multi-ring heterocycles,especially the multi-ring alkaloids.The current relative synthesis methods suffer from the disadvantages of toxic reagents and unsatisfactory yield.In this article,we present a preparation method of nitroalkene with the help of double Henry reaction,acetylated reaction and elimination reaction while using dialdehyde and nitromethane as the raw materials.The total yield of the series of reactions is as high as 86% and the yield of one single batch can reach 20 g. The materials needed for the above-mentioned method are low-cost and easily acquired,the reaction conditions are mild and the after-processing is simple,thus this method can be a highly effective and simple option for the synthesis of nitro-cyclic olefin MBH esters.