Asymmetric Synthesis of Chiral Pyrrolizine-Based Triheterocycles by Organocatalytic Cascade Aza-Michael-Aldol Reactions
作者:Hyo-Jun Lee、Chang-Woo Cho
DOI:10.1002/ejoc.201301260
日期:2014.1
were obtained by the organocatalytic asymmetric cascade aza-Michael–aldol reaction of α-branched α,β-unsaturated aldehydes with 2-(trifluoroacetyl)pyrroles. High enantioselectivities (90–95 % ee) and excellent diastereoselectivities (dr up to >20:1) were achieved by employing this synthetic strategy. The highly functionalized, trifluoromethyl-substituted cascade products have three consecutive stereogenic
通过α-支链α,β-不饱和醛与2-(三氟乙酰基)吡咯的有机催化不对称级联氮杂-迈克尔-羟醛反应,获得了新型手性吡咯嗪基三杂环。通过采用这种合成策略,实现了高对映选择性(90-95% ee)和出色的非对映选择性(dr 高达 >20:1)。高度官能化的三氟甲基取代的级联产物具有三个连续的立体中心,其中包括两个手性四元中心。级联产物与两种不同芳基硼酸的化学选择性逐步 Suzuki 交叉偶联反应以良好的产率提供了基于手性吡咯嗪的三杂环,其中含有两个不同的芳基取代基。