STEREOSELECTIVE[2+1] CYCLOADDITION REACTIONS OF SELENOSILYLETHENE AND ITS APPLICATION TOWARDS SYNTHESIS OF BIOLOGICALLY ACTIVE COMPOUNDS

1.研究了在Lewis酸存在下，1-硒-2-硅基乙烯1与高亲电性的三羰基取代烯烃的反应。在-30ﾟC下，1-苯基-2-亚硒基-2-三甲基硅乙烯(La)与三(烷氧羰基)烯烃2或1，1-二(烷氧羰基)-2-酰基烯烃3在-30ﾟC下反应，完全生成顺式取代的环丙烷。顺式立体化学的起源归因于溴化锌配位的亲电烯烃与1的向斜加成反应。还证明了高度功能化的硒和硅取代的环丙烷产物在制备拟除虫菊酯类杀虫剂的合成中间体方面的应用。[2 11]1-苯基硒-2-三乙基硅乙烯(1b)与二叔丁基亚甲基丙二酸二丁酯(4)在ZnX_2(X=Br，I)存在下的环加成反应，合成了一种新的氨基环丙烷衍生物。环丙烷产物(5)的高官能度被用于立体选择性转化为(E)-2-取代的1-苯胺环丙烷-1-羧酸衍生物，例如(*)-冠花酸和烷基衍生物以及2，3-甲基天冬氨酸衍生物。5中的硒硅甲基作为单一还原的立体控制基，并在随后的步骤中作为甲酰基或羧基的等价物。SnCl4促进的1-硒-2-硅基乙烯1与2-膦-丙烯酸酯6的立体选择性[21]环加成反应高产率地合成了高官能化的环丙烷膦酸酯7。环丙烷产品7可能是生物重要化合物的多种用途的起始原料。以环加成物7b为原料，立体选择性地合成了一种新型的功能化α-氨基膦酸衍生物--(Z)-2，3-甲基高丝氨酸类似物。通过考虑6-SnCl4络合物的结构，解释了[21]环加成反应的立体选择性。

1. The reactions of 1-seleno-2-silylethenes 1 with highly electrophilic tricarbonyl-substitued olefins in the presence of Lewis acids have been investigated. The reaction of 1-phenylseleno-2-trimethylsilylethene (la) with tri(alkoxycarbonyl) olefins 2 or 1,1-di(alkoxycarbonyl)-2-acyl olefins 3 in the presence of ZnBr_2 at -30ﾟC gave cis-substituted cyclopropanes exclusively. The origin of the cis stereochemistry was ascribed to the synclinal addition path of the ZnBr_2-coordinated electrophilic olefin to 1. Application of the highly functionalized selenium- and silicon-substituted cyclopropane products to the preparation of a useful synthetic intermediate, for the pyrethroid class of insecticides was also demonstrated.2. [2+11 Cycloaddition reaction between 1-phenylseleno-2-triethylsilylethene (1b) and di-t-butylmethylene malonate (4) in the presence of ZnX_2 (X = Br, I) was applied to a novel synthesis of aminocyclopropane derivatives. The high functionality of the cyclopropane product (5) was utilized for stereoselective conversion to (E)-2-substituted 1 -anilnocyclopropane-1-carboxylic acid derivatives such as (*)-coronamic acid and an alkyl derivative and a 2,3-methanoaspartic acid derivative. The selenosilylmethyl group in 5 functioned as a stereocontrolling group for mono-reduction and as a formyl or carboxyl group equivalent in the subsequent step.3. Stereoselective SnCl_4-promoted [2+1] cycloaddition reactions of 1-seleno-2-silylethene 1 with 2-phosphonoacrylates 6 lead to highly functionalized cyclopropanephosphonate esters 7 in high yield. The cyclopropane products 7 are potentially versatile starting materials for biologically important compounds. Stereoselective synthesis of a novel functionalized alpha-aminophosphonic acid derivative, an analog of (Z)-2,3-methanohomoserine, from the cycloadduct 7b was achieved. Stereoselectivity in the [2+1] cycloaddition was explained by consideration of the structure of the 6-SnCl_4 complex.