3-乙酰氧基-1-(4-氨基烷基)环己烯的钯(0)催化环化提供了对在组织毒素中发现的1-azaspiro [5.5]十一烷环系统的便捷访问。7-丁基衍生物(4; R 1 = Bu n,R 2 = H)的氢硼化和纯化的硼烷加合物与三甲基氧化胺的氧化提供了N-苄基脱戊基过氢组氨酸毒素,其易于通过氢解转化为(±)-去戊基过氢组氨酸毒素。超过钯碳。
Two stereocontrolledroutes to the alkaloid depentylperhydrohistrionicotoxin 3, are described. The key steps are alkylation, with retention of configuration, of the iodide 8 and the mesylate 12, respectively. A tricyclic aziridinium species is proposed as the reactive intermediate in the latter reaction. The synthesis of 3 represents a formal totalsynthesis of the title alkaloid.