3-Cyclopropyl- and 3-<i>tert</i>-Butyl-Substituted Propyne Iminium Salts as Dienophiles in Diels-Alder Reactions
作者:Gerhard Maas、Holger Gerster、Sigrid Espenlaub
DOI:10.1055/s-2006-942423
日期:2006.7
iminium triflates 7 by N-methylation. These electron-deficient acetylenes were found to be reactive dienophiles in Diels-Alder reactions with cyclopentadiene, furan, 2,3-dimethylbuta-l,3-diene, and anthracene. Reduction of the iminium function, which is present in the cycloaddition products, generates tertiary amines. In this manner, norbornadiene (8, 9), 7-oxanorbornadiene (10, 11), cyclohexa-1,4-diene
从环丙基乙炔和3,3-二甲基-丁-1-炔和亚胺酰氯5开始,制备炔基亚胺6,然后通过N-甲基化转化为丙炔亚胺三氟甲磺酸盐7。在与环戊二烯、呋喃、2,3-二甲基丁-1,3-二烯和蒽的 Diels-Alder 反应中,发现这些缺电子乙炔是活性亲二烯体。存在于环加成产物中的亚胺官能团的还原生成叔胺。以这种方式,降冰片二烯 (8, 9)、7-氧杂降冰片二烯 (10, 11)、cyclohexa-1,4-diene (12)、苯 (13, 14) 和 dibenzobarrelene (15, 16) 衍生物具有新的邻位得到替换模式。