Development of New Synthetic Methods by Use of Heteroatom Elements and their Application to Organic Synthesis

本项目的目的是根据杂原子元素的化学性质，开发新的合成反应，并将其应用于有机合成。代表性结果总结如下。(1)在自由基引发剂存在下，二有机碲化物与碳-碳三键加成，得到相应的乙烯基碲化物。利用该反应，发展了一种立体选择性合成二乙烯基碲化物的方法。(2)通过碲-锂交换反应可以生成多种有机锂化合物，并用于碳-碳形成反应。研究了类金属离子与锂离子交换反应的动力学，如I-Li、Se-Li、Te-Li、Sn-Li交换反应，并通过竞争实验确定了相对交换速率。(3)以硒为催化剂，四胺与一氧化碳进行羰基化反应，合成了一系列独特的环状二脲，并通过X-射线晶体结构分析确定了其结构。通过对硒催化胺羰基化反应的理论计算，提出了生成关键中间体羰基硒的两种可能反应途径。(3)研究了以有机锂、硒、一氧化碳和卤代烷为原料制备硒代酯的新方法。使用异腈代替一氧化碳在类似条件下以良好产率提供硒代亚胺酯。(4)作为自由基羰基化方法的合成应用，我们发展了有机硒化合物的光引发羰基化反应和卤素取代烯烃的双羰基化反应，通过自由基环化反应得到二酮或酮醛。

The aim of this project is to develop the new synthetic reactions based on the characteristics chemical properties of heteroatom elements and to apply these reactions to organic synthesis. The representative results were summarized below. (1) Diorganyl tellurides add to carbon-carbon triple bonds in the presence of a radical initiator to give corresponding vinylic tellurides. By the use of this reaction, a stereoselective synthetic method of divinyl tellurides has been developed. (2) A variety of organolithium compounds have been generated by tellurium-lithium exchange reaction and used for carbon-carbon forming reactions. Kinetic studies of metalloid-lithium exchange, such as I-Li, Se-Li, Te-Li, Sn-Li exchange, have been performed and the relative rates were determined by competitive experiments. (3) Unique cyclic diureas have been synthesized by selenium catalyzed carbonylation of tetraamines with carbon monoxide and their structures were determined by X-ray crystal structure analysis. By the theoretical calculations of selenium catalyzed carbonylation of amines, two possible reaction pathways for the generation of carbonyl selenide, which play an important role as the key intermediate, have been proposed. (3) A new preparative method of selenoesters from organolithiums, selenium, carbon monoxide, and alkyl halides has been developed. The use of isonitriles instead of carbon monoxide affords selenoimidates in good yields under similar conditions. (4) As the synthetic application of radical carbonylation methodology, we developed photoinitiated carbonylation of organoselenium compounds and double carbonylation of halogen substituted alkenes which gives diketones or ketoaldehydes via radical cyclization.