Development of new catalytic systems for efficient use of carbon monoxide

开发高效的一氧化碳利用方法是化学工业中最重要的课题之一。这个项目就是为此目的而设立的，重点是开发使用元素硒代替过渡金属的新催化体系，过渡金属经常用于将一氧化碳引入有机分子。本项目的研究结果总结如下：已发现，硒对各种含有质子氢的有机分子，如胺、醇和硫醇与一氧化碳的羰基化反应具有极高的催化活性。将该反应应用于二胺和氨基醇，得到了合成环状尿素和环状氨酯的有效方法。对硒催化胺的羰化反应生成尿素衍生物的详细研究表明，该反应是通过氨基硒酸酯和双氨基甲酰二硒醚作为关键中间体进行的。Se的高活性可能是由于Se和一氧化碳容易生成羰基硒(Se=C=O)，它很容易与反应体系中的亲核试剂反应。合成了几种含有Seco基团的有机硒化合物。对这些化合物的合成活性的考察表明，双氨基甲酰二硒醚和硒-烷基硒碳酸酯分别可作为氨甲酰化试剂和氧羰化试剂。除了这种硒辅助的羰基化，还开发了一种新的方法，通过一氧化碳、氢硅烷和羰基钴的联合使用来合成酯和缩醛，其中一氧化碳以硅氧甲基的形式加入到产物中。

Development of efficient methods for the use of carbon monoxide is one of the most important subjects in the chemical industry. This project has been set up for this purpose focussing on the development of new catalytic system using elemental selenium rather than transition metals which have been frequently used for introduction of carbon monoxide into organic molecules. The results obtained in this project are summarized below.Selenium has been found to have an extremely high catalytic activity for carbonylation with carbon monoxide of a variety of organic molecules having protic hydrogen such as amines,alcohols,and thiols. Application of this reaction to diamines and aminoalcohols results in achievement of efficient methods for the syntheses of cyclic ureas and cyclic urethanes. A delailed study on the selenium catalyzed carbonylation of amines leading to urea derivatives has revealed that the reaction proceeds via carbamoselenoate and biscarbamoyl diselenide as the key intermediates. Such a high activity of selenium for the carbonylation may be based on the facile formation of carbonyl selenide (Se=C=O) from selenium and carbon monoxide, which reacts readily with nucleophiles in the reaction system. Several types of organoselenium compounds in which SeCO moiety is incorporated have been synthesized. Examination of synthetic utility of these compounds revealed that biscarbamoyl diselenides and Se-alkyl selenocarbonates can be used as carbamoylating and oxycarbonylating reagents, respectively. In addition to this selenium assisted carbonylation, a new method for homologation of esters and acetals by combined use of carbon monoxide, hydrosilanes and cobalt carbonyl has been developed, where carbon monoxide is incorporated as siloxymethyl group in the products.