Dirhodium(II)-Catalyzed Intramolecular Carbon-Hydrogen Insertion Reaction of .ALPHA.-Diazoketones: Synthesis of 7-Silyloxyoctahydrobenzo(b)furan-2-ones.
作者:Takayuki YAKURA、Daisaku YOSHIDA、Akiharu UEKI、Keiko NAKAO、Masazumi IKEDA
DOI:10.1248/cpb.45.651
日期:——
A dirhodium(II)-catalyzed intramolecular C-H insertion reaction of 2-oxygen-substituted cyclohexyl diazoacetoacetates 1a-f was investigated. In contrast to the trans-2-methoxy- 1a and trans-2-(p-methoxybenzyloxy)-cyclohexyl derivatives 1b, which, upon treatment with 1 mol% dirhodium(II) tetraacetate in boiling benzene, gave a complex mixture, the trans-2-(tert-butyldimethylsilyoxy)cyclohexyl derivative 1c gave, in addition to the β-lactone 3c (16%), cis- and trans-fused octahydrobenzo[b]furan-2-ones 2c in 22 and 18% yields, respectively. Similar treatment of the cis-isomer 1d gave the β-lactone 3d as the major product (34%) and cis- and trans-fused γ-lactones 2d (7 and 18% yields, respectively) as minor products. The (1R*, 2R*, 3R*)-3-benzyloxy-2-(tert-butyldimethylsilyloxy)cyclohexyl derivative 1e gave the γ-lactones 2e in 75% combined yield as a 5 : 2 mixture of cis- and trans-fused isomers, while the (1R*, 2R*, 3R*)-isomer 1f afforded the trans-fused γ-lactone 2f in 62% yield as a single product.
研究了 2-氧取代的环己基重氮乙酰乙酸酯 1a-f 的分子内 C-H 插入反应。与反式-2-甲氧基-1a 和反式-2-(对甲氧基苄氧基)-环己基衍生物 1b 不同,反式-2-(对甲氧基苄氧基)-环己基衍生物 1b 在沸腾的苯中用 1 mol% 的四乙酸二铑(II)处理后,得到一种复杂的混合物、反式-2-(叔丁基二甲基硅氧基)环己基衍生物 1c 除得到 β-内酯 3c (16%)外,还得到顺式和反式融合的八氢苯并[b]呋喃-2-酮 2c,收率分别为 22% 和 18%。对顺式异构体 1d 进行类似处理后,主要产物为 β-内酯 3d(34%),次要产物为顺式和反式融合的 γ-内酯 2d(产率分别为 7% 和 18%)。(1R*,2R*,3R*)-3-苄氧基-2-(叔丁基二甲基硅氧基)环己基衍生物 1e 以顺式和反式融合异构体 5 : 2 的混合物形式得到了γ-内酯 2e,总产率为 75%,而 (1R*,2R*,3R*)-异构体 1f 以单一产物形式得到了反式融合的γ-内酯 2f,产率为 62%。