Torsional effects influence kinetic selectivity in a wide range of organic transformations. As such, textbooks commonly use Newman projections to illustrate the torsional effects that arise in their transition states. Unfortunately, these representations fall short when the reaction occurs within a ring. In many cases, the torsional preferences of the ring and the stereoelectronic (orbital) requirements of the reaction can lead to either a chair or twist-boat transition state. The aim of this communication is to shed light on these effects and to describe a new method to draw and visualize the associated chair and twist-boat transition state structures.

中文翻译：

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可视化扭转控制加成反应中椅子和扭曲板转变态的简单方法

扭转效应在广泛的有机转化中影响动力学选择性。这样，教科书通常使用纽曼投影来说明在其过渡状态中产生的扭转效应。不幸的是，当反应在环内发生时，这些表示就不够了。在许多情况下，环的扭转偏好和反应的立体电子（轨道）要求可能导致椅子或扭转船过渡状态。交流的目的是阐明这些效果，并描述一种绘制和可视化相关的椅子和扭曲船过渡状态结构的新方法。