Development of catalytic asymmetric reactions based on design and synthesis of original chiral ligands

针对催化不对称反应的新型手性配体的合理设计和合成是目前合成有机化学研究的热点。我们合成了新型的手性化合物，包括螺联并二亚磷酸盐、双恶唑和N-氧化物，它们被用作手性配体用于几种不对称反应。主要研究结果如下：(1)利用双偶氮类化合物在手性铑(II)催化下的双分子内C-H插入反应，实现了光学活性1，1‘-螺联并-3，3’-二酮类化合物的高效一锅构筑。螺联二酮很容易转化为螺联二亚磷酸酯，是钯催化的烯丙基烷基化反应和铑催化的Pauson-Khandd反应的有效手性配体。(2)新型双恶唑啉配体是一种高效的铜催化Diels-Alder反应和环丙烷化反应的手性配体。(3)在手性铑(H)络合物的辅助下，重氮酯的烯丙基氧或硫叶立德的分子内串联生成和重排反应被实现。(4)以手性联吡啶-N，N‘-二氧化镉络合物为催化剂，对硫醇的不对称共轭加成反应进行了研究。(5)在手性N，N‘-二氧化钪络合物催化下，β-酮酯与甲基乙烯基酮的不对称Michael加成反应得到了具有良好对映体选择性的a-Michael加合物。(6)手性N，N‘-氧化物催化中位环氧化物与四氯化硅对映选择性开环反应生成光学活性氯醇。

The rational design and synthesis of novel chiral ligands directed toward catalytic asymmetric reactionsis currently the focus of attention in synthetic organic chemistry. We have synthesized novel chiral compounds including spirobiindanbisphosphites, bisoxazolines, and N-oxides, which were utilized in several enantioselective reactions as chiral ligands. The results we have obtained are as follows; (1) A highly efficient one-pot construction of optically active 1,1'-spirobiindan-3,3'-dione derivatives has been achieved by exploiting double intramolecular C-H insertion reaction of bisdiazo compounds catalyzed by chiral rhodium(II) complex. The spirobiindandione was easily converted to spirobiindanbisphosphite, which was found to be an efficient chiral ligand for palladium-catalyzed allylic alkylation and rhodium-catalyzed Pauson-Khand reaction. (2) Novel bisoxazoline ligands prepared via rhodium-catalyzed enantioselective C-H insertion reaction have proven to be an efficient chiral ligand for copper-catalyzed Diels-Alder reaction and cyclopropanation. (3) Tandem intramolecular generation and rearrangement of allylic oxomium or sulfonium ylides from diazoesters has been effected with the aid of chiral rhodium(H) complex. (4) A novel method of enantioselective conjugate additions of thiols produced sulfides employing a cadmium complexes of chiral bipyridine N,N'-dioxide as a catalyst. (5) An enantioselective Michael addition of β-keto esters to methyl vinyl ketone employing a chiral N,N'-dioxide-scandium complex as a catalyst afforded the a Michael adduct with good enantioselectivity. (6) Chiral N,N'-dioxides catalyzed enantioselective ring opening of meso-epoxides with silicon tetrachloride to produce optically active chlorohydrins.