Annulation of imidazolines: A 1,3-dipolar cycloaddition route to pyrroloimidazoles, pyrrolidines and pyrroles
作者:Raymond C.F. Jones、John R. Nichols、Michael T. Cox
DOI:10.1016/0040-4039(90)80221-7
日期:1990.1
Azomethine ylides, prepared from imidazolinium salts, undergo 1,3-dipolar cycloaddition with a variety of dipolarophiles to produce hexahydropyrrolo[1,2-a]imidazoles, which are reduced to pyrrolidines; with 2-chloroacrylonitrile as dipolarophile, pyrroles can be prepared from the cycloadducts by elimination.
由咪唑啉鎓盐制得的偶氮甲亚胺与多种偶极亲和剂进行1,3-偶极环加成反应,生成六氢吡咯并[1,2- a ]咪唑,并还原为吡咯烷;用2-氯丙烯腈作为双极性亲和剂,可以通过消除从环加合物制备吡咯。
Annulation of dihydroimidazoles: a 1,3-dipolar cycloaddition route to pyrrolo[1,2-a]imidazoles, pyrrolidines and pyrroles
作者:Raymond C. F. Jones、Kevin J. Howard、John R. Nichols、John S. Snaith
DOI:10.1039/a802048e
日期:——
4,5-Dihydroimidazolium ylides, formed by N-alkylation of 4,5-dihydroimidazoles, undergo diastereoselective endo 1,3-dipolar cycloaddition with electron-deficient alkene dipolarophiles to afford hexahydropyrrolo[1,2-a]imidazoles; reduction of the aminal functionality in the cycloadducts leads to substituted pyrrolidines. Cycloaddition using 2-chloropropenonitrile, followed by base treatment, affords pyrroles.