Control of Chemoselectivity in Dirhodium(II)-Catalyzed Reaction of 5,6-Dioxygenated 2-Diazo-3-oxohexanoates: C-H Insertion Reaction versus Oxonium Ylide Formation.
作者:Takayuki YAKURA、Akiharu UEKI、Yukiko MORIOKA、Toyoshige KURATA、Kenji TANAKA、Masazumi IKEDA
DOI:10.1248/cpb.46.1182
日期:——
Methyl (S)-2-diazo-4-(3, 3-dimethyl-2, 4-dioxolan-1-yl)-3-oxobutanoate (1), upon treatment with Rh2(OAc)4 in boiling dichloromethane, gave methyl (1S, 5S)-2, 2-dimethyl-7-oxo-3, 8-dioxabicyclo[3.2.1]octane-1-carboxylate (2) via oxonium ylide formation/1, 2-shift. On the other hand, similar treatment of methyl (S)-5, 6-bis(tert-butyldimethylsilyloxy)-2-diazo-3-oxohexanoate (3a) gave methyl 3-(tert-butyldimethylsilyloxy)-5-oxo-1-cyclopentene-1-carboxylate (4a) via the C-H insertion reaction.
(S)-2-重氮-4-(3, 3-二甲基-2, 4-二氧戊环-1-基)-3-氧代丁酸甲酯(1)在沸腾的二氯甲烷中用 Rh2(OAc)4 处理后,通过羰基锍形成/1, 2-移位,得到(1S, 5S)-2, 2-二甲基-7-氧代-3, 8-二氧杂环[3.2.1]辛烷-1-甲酸甲酯(2)。另一方面,通过 C-H 插入反应,对 (S)-5,6-双(叔丁基二甲基硅氧基)-2-重氮-3-氧代己酸甲酯(3a)进行类似处理,可得到 3-(叔丁基二甲基硅氧基)-5-氧代-1-环戊烯-1-甲酸甲酯(4a)。