Synthesis of (±)-Acetylnorloline via Stereoselective Tethered Aminohydroxylation

Loline alkaloids exhibit a strained ether-bridged pyrrolizidine skeleton and possess insecticidal and insect antifeedant properties. The synthesis of acetylnorloline, a prototypical member of the alkaloid family, is described. Central to the route is a stereoselective tethered aminohydroxylation (TA) of a homoallylic carbamate. Allylic (A1,3) strain is exploited to enforce diastereofacial selectivity during the aminohydroxylation.

Loline生物碱（Loline alkaloids）具有张力醚桥吡咯里西啶骨架，同时具备杀虫活性与昆虫拒食活性。本文报道了该生物碱家族典型成员乙酰基去甲洛林碱（acetylnorloline）的合成路线。该路线的核心步骤为对高烯丙基氨基甲酸酯进行立体选择性锚定氨基羟基化反应（tethered aminohydroxylation，TA）。研究中借助烯丙基（A1,3）张力，在该氨基羟基化反应过程中实现非对映面选择性的调控。