英国南安普顿大学Goldup Stephen M报道了机械轴向手性链状烷和非典型机械轴向手性轮烷。相关研究成果于2022年6月27日发表在国际顶尖学术期刊《自然—化学》。
手性通常出现在分子中，因为共价键合原子的刚性手性排列。不太普遍认识到的是，当分子相互穿插形成机械键时，会产生手性。例如，当两个具有不同化学表面的大环连接形成一个链烷时，结构是手性的，尽管环本身不是。然而，机械键为立体化学提供唯一来源的对映体纯机械轴向手性链烷尚未报道。
该文中，研究人员再次研究了这些分子的对称性，并在此过程中确定了从简单的手性构建块获得它们的直接途径。该分析还使研究人员确定了一个类似但以前未标记的轮烷立体单元，这也产生了共构象辅助方法。利用手中的机械轴向手性分子的方法，现在可以探索它们的性质和应用。尽管机械轴向手性（MAC）链烷在1961年被发现，但其立体选择性合成迄今尚未公开。对对MAC立体单元的进一步研究还发现了一种类似的但未被提及的轮烷立体化学形式，并形成了一种立体选择性制备MAC分子的一般方法。
附：英文原文
Title: Mechanically axially chiral catenanes and noncanonical mechanically axially chiral rotaxanes
Author: Maynard, John R. J., Gallagher, Peter, Lozano, David, Butler, Patrick, Goldup, Stephen M.
Issue&Volume: 2022-06-27
Abstract: Chirality typically arises in molecules because of a rigidly chiral arrangement of covalently bonded atoms. Less generally appreciated is that chirality can arise when molecules are threaded through one another to create a mechanical bond. For example, when two macrocycles with chemically distinct faces are joined to form a catenane, the structure is chiral, although the rings themselves are not. However, enantiopure mechanically axially chiral catenanes in which the mechanical bond provides the sole source of stereochemistry have not been reported. Here we re-examine the symmetry properties of these molecules and in doing so identify a straightforward route to access them from simple chiral building blocks. Our analysis also led us to identify an analogous but previously unremarked upon rotaxane stereogenic unit, which also yielded to our co-conformational auxiliary approach. With methods to access mechanically axially chiral molecules in hand, their properties and applications can now be explored. Despite mechanically axially chiral (MAC) catenanes being recognized in 1961, their stereoselective synthesis had not been disclosed until now. Closer inspection of the MAC stereogenic unit has also led to the identification of an analogous, but unremarked upon, form of rotaxane stereochemistry and the conceptualization of a general approach to prepare MAC molecules stereoselectively.
DOI: 10.1038/s41557-022-00973-6
