A highly stereoselective synthesis of (6S*, 7S*, 8S*)-7-butyl-8-hydroxy-1-azaspiro [5.5]-undecan-2-one (6), a key intermediate for (±)-perhydrohistrionicotoxin synthesis, from the Diels-Alder cycloadduct of 1, 3-bis (trimethylsiloxy)-2-methyl-1, 3-butadiene (15) and ethyl 3-acetoxy-1-cyclohexene-1-carboxylate is described. This key intermediate and its stereoisomer, (6R*, 7S*, 8S*)-7-butyl-8-hydroxy-1-azaspiro [5.5] undecan-2-one (7), were stereoselectively synthesized by means of a conjugate addition reaction using 1-(3-tert-butyldimethylsiloxy-1-cyclohexen-1-yl)-ethanone and BuCu·AlCl3 as the key step.
(6S*, 7S*, 8S*)-7-丁基-8-羟基-1-氮杂螺[5.5]-
十一烷-2-酮 (6) 的高度立体选择性合成,(±)-全氢组
氨酸毒素合成的关键中间体,描述了1, 3-双(三甲基
硅氧基)-2-甲基-1, 3-
丁二烯(15)和3-乙酰氧基-1-
环己烯-1-
甲酸乙酯的Diels-Alder环加合物。该关键中间体及其立体异构体,(6R*, 7S*, 8S*)-7-丁基-8-羟基-1-氮杂
螺[5.5]十一烷-2-酮(7),通过共轭加成立体选择性合成以1-(3-叔丁基二甲基
硅氧基-1-
环己烯-1-基)-乙酮和BuCu·
AlCl3为关键步骤进行反应。