Reactions of <i>N</i>-(Ethoxycarbonyl)-3-halo-3-(halomethyl)azetidines with DBU. The Halogen Dance
作者:Alan P. Marchand、Arokiasamy Devasagayaraj
DOI:10.1021/jo970166r
日期:1997.6.1
Reaction of N-(ethoxycarbonyl)-3-(bromomethyl)-3-chloroazetidine (3) with DBU results in the formation of two haloalkenes, i.e., N-(ethoxycarbonyl)-3-(bromomethylene)azetidine and N-(ethoxycarbonyl)-3-(chloromethylene)azetidine (4a and 4b, respectively). The results of control experiments suggest that Cl(-) is capable of promoting nucleophilic displacement of bromine in the CH(2)Br groups of both 3
N-(乙氧羰基)-3-(溴甲基)-3-氯氮杂环丁烷(3)与DBU的反应导致形成两个卤代烯烃,即N-(乙氧羰基)-3-(溴亚甲基)氮杂环丁烷和N-(乙氧羰基) -3-(氯亚甲基)氮杂环丁烷(分别为4a和4b)。对照实验结果表明,Cl(-)能够促进3和N-(乙氧基羰基)-3-bromo-3-(溴甲基)氮杂环丁烷的CH(2)Br基中溴的亲核取代(8) ,但Br(-)无法取代N-(乙氧羰基)-3-氯-3-(氯甲基)氮杂环丁烷(7)和N-carbethoxy-3-bromo-3的CH(2)Cl基团中的氯-(氯甲基)氮杂环丁烷(10)。因此,建议通过3与DBU的反应形成4b是DBU促进从关键反应中间体7中除去HCl的结果。