Utilization of Meso Substrates by Catalytic Asymmetrization Reaction

研究了手性BINAP配体与铑阳离子配合物催化的不对称烯烃迁移反应。起初，以环戊二烯和苯醌容易制备的二元醇和类似物为底物，在研究过程中发现：1）以二醇为底物时，光学产率为43%。2）得到了几乎完美的结果，当使用双硅烷基醚时，3）光学产率与硅烷基官能团的体积无关; 4）双烷基醚没有带来良好的对映体过量; 5）双酯根本不起作用; 6）烯烃迁移的过程在二醇和双酯之间是相反的。接下来，将该方法进一步应用于7元内消旋-烯-二醇。首次从异构化产物中合成了托品烷类生物碱毒扁豆碱。

The asymmetric olefin migration reaction catalyzed by the cationic Rh-complex ligated with chiral BINAP had been investigated. At the beginning, the diol and the analogus which were easily prepared from the cyclopentadiene and benzoquione were used as the substrates.The following facts were discovered during investigation :1) The optical yield was 43%, when the diol was used as the substrate.2) The almost perfect results were obtained, when the bis-siltl ethers were used.3) The optical yield does not related to the bulkiness of the silyl functional group.4) The bis-alkyl ethers did not bring about good enantiomeric excess.5) The bis-ester did not work at all.6) The course of the olefin migration was inversely between the diol and the bis-silyl ether.Next, this methodology was further applied to the 7-membered meso-ene-diol. The first enantiomeric synthesis of the tropane alkaloid, physoveruvine was achieved from the isomerized product.