Nitrile Anion Cyclization with Epoxysilanes Followed by Brook Rearrangement/Ring-Opening of Cyclopropane Nitriles/Alkylation
作者:Seigo Okugawa、Hyuma Masu、Kentaro Yamaguchi、Kei Takeda
DOI:10.1021/jo0519413
日期:2005.12.1
9−12 with a base and an alkylating agent affords (Z)-δ-siloxy-γ,δ-unsaturated pentanenitrile derivatives via a tandem process that involves the formation of a cyclopropane derivative by epoxy nitrile cyclization followed by Brook rearrangement and an anion-induced cleavage of the cyclopropane ring. Exclusive formation of a (Z)-derivative from trans-epoxides is explained by the reaction pathway that involves
δ -甲硅烷基-γ,δ-epoxypentanenitrile衍生物的反应9 - 12用碱和烷基化剂,得到(ż)-δ-甲硅烷氧基-γ,通过串联的过程,涉及环丙烷的形成δ不饱和戊腈衍生物环氧腈环化反应,然后进行布鲁克重排和阴离子诱导的环丙烷环裂解,生成环戊二烯衍生物。由反式环氧化物独家形成(Z)衍生物的反应途径包括通过α-腈碳负离子和O-Si键形成环氧化物的背面置换以及随后涉及Brook重排和反式的协同过程旋转器19消除环丙烷的环裂变模式。(E)-异构体仅从顺式-环氧化物和α-环丙基-α-甲硅烷基甲醇衍生物26获得的事实为提出的途径提供了实验支持。