describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiral N-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline
我们描述了使用 BINOL 衍生的手性N-三氟甲基磷酰胺的简单 2-烯基苯甲醛二亚胺的催化不对称亚胺离子环化反应。相应的 1-氨基茚和四环 1-氨基茚以良好的产率和高对映选择性形成。此外,所获得的对映体纯 1-氨基茚的化学效用被证明用于 ( S )-雷沙吉兰的不对称合成。
Stereoselective Synthesis of Chiral IBR2 Analogues
作者:Xiao-Long Qiu、Jiewen Zhu、Guikai Wu、Wen-Hwa Lee、A. Richard Chamberlin
DOI:10.1021/jo802607f
日期:2009.3.6
Two stereoselective routes were developed to synthesize optically pure IBR2 analogues 1-16. The first features addition of N-Boc-3-bromoindole 26 to the sulfinamide 25, providing a 1: 1 ratio of the separable diasteroisomers 27 and 28 in good yield. In a straightforward fashion, the sulfinamides 27 and 28 were conveniently converted into the key amines 39 and 47 over 8 steps, respectively, from which a series of 3,4-dihydroisoquinolinyl IBR2 analogues 1-14 containing fluorinated and trifluoromethylated benzyl groups were prepared. Another route highlights the highly enantioselective addition of indole to the sulfonyl amide 50 with bifunctional aminothioureas 57 and 58 as catalysts. After the reaction conditions were optimized, the desired sulfonyl amides (R)-55 and (S)-55 were obtained in 99% ee and 98% ee, respectively. Acylation of (R)-55 and (S)-55 separately and subsequent allylation gave compounds 60 and 63, respectively, which were further subjected to RCM to furnish compounds 61 and 64 and, after removal of the Boc groups, the desired IBR2 analogues 15 and 16.