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

1.研究了在刘易斯酸存在下1-硒基-2-硅基乙烯1与高度亲电的三羰基取代烯烃的反应。1-苯硒基-2-三甲硅基乙烯（Ia）与三烷氧羰基烯烃2或1，1-二烷氧羰基-2-酰基烯烃3在ZnBr_2存在下于-30 ℃反应，只生成顺式取代的环丙烷。顺式立体化学的起源归因于ZnBr_2配位的亲电烯烃对1的向斜加成路径。高度官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有用合成中间体中的应用也得到了证明.在ZnX_2（X = Br，I）存在下，1-苯硒基-2-三乙基硅基乙烯（1b）与亚甲基丙二酸二叔丁酯（4）发生[2+11]环加成反应，合成了氨基环丙烷衍生物。环丙烷产物（5）的高官能度用于立体选择性转化成（E）-2-取代的1 -苯胺基环丙烷-1-羧酸衍生物，例如（*）-冠酰胺酸和烷基衍生物和2，3-甲氨基天冬氨酸衍生物。5中的硒代甲硅烷基甲基作为单还原的立体控制基团，并在随后的步骤中作为甲酰基或羧基的等价物。SnCl_4促进的1-硒基-2-硅基乙烯1与2-膦酰基丙烯酸酯6的[2+1]环加成反应高产率地合成了高度官能化的环丙烷膦酸酯7。环丙烷产物7是用于生物学上重要的化合物的潜在通用起始材料。实现了从环加成物7 b立体选择性合成新型官能化α-氨基膦酸衍生物（（Z）-2，3-亚甲基高丝氨酸的类似物）。[2+1]环加成反应的立体选择性可从6-SnCl_4配合物的结构得到解释。

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.