Syntheses of Isoprenoids by Telomerizations. IX. Stereoselectivity of Telomers and the Effect of Telogens in Anionic Telomerizations Using Secondary Amines
作者:Kunihiko Takabe、Takao Katagiri、Juntaro Tanaka
DOI:10.1246/bcsj.46.222
日期:1973.1
The stereoselectivity of the telomers and the effect of the telogens in the anionic telomerizations of isoprene with secondary amines were investigated. Dimethyl-, diethyl-, di-n-propy-1, diisopropyl-, and methylphenyl-amines, pyrrolidine, morpholine, and piperidine were used as the telogens. The ratio of N,N-dialkyl(3,7-dimethyl-2,6-octadienyl)amine(2A) to N,N-dialkyl(2-isopropenyl-5-methyl-4-hexenyl)amine(2B), which were obtained in these reactions, was varied with the sort of secondary amines, the yield of the telomers was found to be dependent on the acidity of the secondary amines. Moreover, 2A, which was the main component of the n=2 telomers, was confirmed to have a cis-configuration—that is, N,N-dialkylnerylamine. However, the n=1 telomer of myrcene with secondary amine was N,N-dialkylgeranylamine. These results were interpreted in terms of the stability of the cyclic intermediate of the carbanions.
研究了异戊二烯与二级胺进行阴离子延长聚合反应中的延长剂的立体选择性及其影响。使用了二甲基、二乙基、正丙基、异丙基和甲基苯胺、吡咯烷、哌啶和吗啉作为延长剂。反应中获得的N,N-二烷基(3,7-二甲基-2,6-辛二烯基)胺(2A)与N,N-二烷基(2-异丙烯基-5-甲基-4-己烯基)胺(2B)的比例随着二级胺的种类变化,且延长聚合物的产率与二级胺的酸性相关。此外,确认n=2延长聚合物的主要成分2A具有顺式构型,即N,N-二烷基尼烯胺。然而,与二级胺反应的美克烯的n=1延长聚合物为N,N-二烷基杰拉尼胺。这些结果可以通过羰基阴离子环状中间体的稳定性进行解释。