1-烯丙氧基-2-甲氧基甲氧基苯Claisen重排反应研究

Study of Claisen rearrangement of 1-allyloxy-2-methoxymethoxybenzene

在碱性条件下,邻苯二酚与CH3OCH2Cl反应得到邻羟基醚2,化合物2进一步与烯丙基溴反应得到重要中间体1-烯丙氧基-2-甲氧基甲氧基苯3,以3为Claisen重排前体原料,在200～210℃,弱氧化剂硝基苯的存在下,模拟Photo-Claisen Rearrangement反应过程,得到了对位重排产物4和常规Claisen重排所得不到的间位产物5,从而证明了在此条件下,有单线态和三线态自由基的产生,并对反应机理进行了推测.相关中间体及产物的结构通过IR、1HNMR表征,表明成功合成了上述化合物,并对结果进行了合理的分析.

In our study, pyrocatechol reacts with CH3OCH2Cl to produce 2-hydroxybenzyl ether 2. Compound 2 then reacts with allyl bromide to generate the key intermediate 1-allyloxy-2-methoxyme- thoxybenzene 3. The Claisen rearrangement of 3 has been examined in nitrobenzene as solvent and the weak oxidizing agent at 200-210℃ to simulate photo-Claisen rearrangement process, which can obtain para rearrangement product 4 and the informal 3-substituted product 5. It indicats that the existence of singlet radical pair and triplet radical pair. The radical pair mechanism has been well-established based on previous literature. The structures of all compounds have already been characterized by IR and ^1 HNMR. All compounds are synthesized successfully and the rational analysis is given.