A Chiral Synthesis of the Strychnos and Ophiorrhiza Alkaloid Normalindine
作者:Masashi Ohba、Hiroyuki Kubo、Hiroyuki Ishibashi
DOI:10.1016/s0040-4020(00)00695-5
日期:2000.9
A full account of the first chiral synthesis of (−)-normalindine [(−)-4], an indolopyridonaphthyridine alkaloid isolated from Strychnos johnsonii and Ophiorrhiza filistipula, is presented. Central features of the synthetic strategy include the conversion of l-alanine methyl ester (13) into the oxazole derivative 12 and the intramolecular Diels–Alder reaction of the oxazole–olefin derivatives 27a and
An efficient and general preparation of several chiral N-protected 5-(aminomethyl)oxazoles has been accomplished by treatment of N-protected α-amino esters with α-lithiated isocyanides, obtained by metalation of methyl and benzyl isocyanides with BuLi or of ethyl isocyanide with lithium diisopropylamide.
通过将甲基和苄基异氰酸酯与 BuLi 金属化,或将乙基异氰酸酯与二异丙基酰胺锂金属化,可以用 α-硫代异氰酸酯处理 N 保护的 α-氨基酯,从而高效而普遍地制备出多种手性 5-(氨基甲基)噁唑。
Formation of the 1H-Pyrrolo[3,4-c]pyridin-1-one Skeleton via Intramolecular Diels-Alder Reaction of Oxazoles
The 1H-pyrrolo[3,4-c]pyridin-1-one derivatives (4a-c) were prepared through a route employing the intramolecular Die Is Alder reaction of the oxazole-olefins (3a-c). Conversion of the crotonamide (3a) into 4a was effectively promoted by the addition of Cu(OTf)(2) as a catalyst.