Enamino Ester Reduction: A Short Enantioselective Route to Pyrrolizidine and Indolizidine Alkaloids. Synthesis of (+)-Laburnine, (+)-Tashiromine, and (−)-Isoretronecanol
作者:Olivier David、Jérôme Blot、Christian Bellec、Marie-Claude Fargeau-Bellassoued、Gjergj Haviari、Jean-Pierre Célérier、Gérard Lhommet、Jean-Claude Gramain、Daniel Gardette
DOI:10.1021/jo982169p
日期:1999.4.1
over Pd/C gave rise to the higher diastereoselectivity and mainly afforded the unexpected anti addition product (e.d. 84%). The scope of these reductions has been extended to the synthesis of three pyrrolizidine or indolizidine alkaloids: (+)-tashiromine, (+)-laburnine, and (-)-isoretronecanol. Syntheses of these natural products, starting from chiral beta-enamino diesters, were achieved in a short and
由于源自(S)-α-甲基苄胺的手性诱导,各种手性吡咯烷四取代的β-烯氨基酯以良好或中等的非对映选择性被催化或化学还原。使用环内双键化合物,使用PtO(2)作为加氢催化剂可获得最佳结果,并导致主要的合成加成产物(ed 90%)。在环外双键化合物的情况下,在Pd / C上进行氢化会产生更高的非对映选择性,并主要提供意想不到的抗加成产物(84%)。这些减少的范围已扩展到三种吡咯烷或生物碱的合成:(+)-tashiromine,(+)-laburnine和(-)-异戊烯醇。从手性β-烯胺二酯开始合成这些天然产物,