英国南安普顿大学Goldup, Stephen M.团队开发了平面机械手性轮烷合成的手性连锁辅助策略。相关研究成果发表在2021年11月29日出版的《自然—化学》。

轮烷在不存在共价立体单元的情况下，之所以能显示分子手性，完全是因为轴与环大环之间的机械键合，该分子的合成仍然具有挑战性。

研究人员发现了一种反应伙伴的组合，起着手性联锁辅助作用，既能定向大环，又能有效地将其加载到一个新的轴上。该文中，研究人员使用该底物通过生产一系列具有高对映体纯度（93–99%e.e.）的实例，来证明手性联锁辅助策略在机械平面手性轮烷合成中的潜力，包括所谓的“不可能的”轮烷，其轴缺少任何官能团，从而无法通过其他方式直接合成。有趣的是，通过改变键形成步骤的顺序，研究人员可以有效地选择将大环加载到轴的哪一端，从而能够使用相同的反应和构建块合成单个目标的双手。

附：英文原文

Title: A chiral interlocking auxiliary strategy for the synthesis of mechanically planar chiral rotaxanes

Author: de Juan, Alberto, Lozano, David, Heard, Andrew W., Jinks, Michael A., Suarez, Jorge Meijide, Tizzard, Graham J., Goldup, Stephen M.

Issue&Volume: 2021-11-29

Abstract: Rotaxanes can display molecular chirality solely due to the mechanical bond between the axle and encircling macrocycle without the presence of covalent stereogenic units. However, the synthesis of such molecules remains challenging. We have discovered a combination of reaction partners that function as a chiral interlocking auxiliary to both orientate a macrocycle and, effectively, load it onto a new axle. Here we use these substrates to demonstrate the potential of a chiral interlocking auxiliary strategy for the synthesis of mechanically planar chiral rotaxanes by producing a range of examples with high enantiopurity (93–99% e.e.), including so-called ‘impossible’ rotaxanes whose axles lack any functional groups that would allow their direct synthesis by other means. Intriguingly, by varying the order of bond-forming steps, we can effectively choose which end of an axle the macrocycle is loaded onto, enabling the synthesis of both hands of a single target using the same reactions and building blocks.

DOI: 10.1038/s41557-021-00825-9

Source: https://www.nature.com/articles/s41557-021-00825-9