A highly efficient synthesis of the enantioenriched tetrahydro-β-carbolines was developed by using a chiral phosphoric acid catalyzed Pictet–Spengler reaction of indolyl dihydropyridines. The reaction proceeds under mild reaction conditions to afford the desired chiral tetrahydro-β-carbolines in good to excellent yields (up to 96 %) and high enantioselectivities (up to 99 % ee). With this method, a formal synthesis of tangutorine and a total synthesis of deplancheine were achieved in a highly efficient manner.

中文翻译：

---

手性四氢-β-咔啉的构建：吲哚基二氢吡啶的不对称Pictet-Spengler反应

通过使用手性磷酸催化吲哚基二氢吡啶的Pictet-Spengler反应，开发了对映体富集的四氢-β-咔啉的高效合成方法。反应在温和的反应条件下进行，以良好的产率（高达96％）和高的对映选择性（高达99％ee）提供所需的手性四氢-β-咔啉。用这种方法，可以高效地完成橘皮苷的正式合成和十氢萘烷的全部合成。