Racemic natural products with complex molecular structures have inspired chemists for decades. Their widespread occurrence raises interesting biosynthetic questions and poses (retro)synthetic challenges. Using some classic examples and representative work from the recent literature, we show how biomimetic synthesis can address some of these questions and challenges, provide insights into the formation of such molecules in nature, and enable efficient access to them in the laboratory. The importance of stereoselective reaction cascades that involve cycloadditions, electrocyclizations, phenolic oxidations, and Mannich, Michael, and Aldol reactions is highlighted. In the absence of chiral information, these cascades form racemates from achiral precursors. Their stereochemical complexity can be increased further when these racemic products undergo homochiral or heterochiral dimerizations.

具有复杂分子结构的外消旋天然产物数十年来一直启发化学家。它们的广泛出现引发了有趣的生物合成问题，并提出了（复古）合成挑战。通过使用一些经典的例子和最新文献中的代表性作品，我们展示了仿生合成如何解决其中的一些问题和挑战，提供有关自然界中此类分子形成的见解，并能够在实验室中有效地使用它们。强调了涉及环加成，电环化，酚醛氧化以及曼尼希，迈克尔和阿尔多反应的立体选择性反应级联的重要性。在没有手性信息的情况下，这些级联反应由非手性前体形成外消旋体。