Torsional effects influence the stereochemical outcome of 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.  We have taken a closer look at these reactions and present a simple method to visualize and draw their associated chair and twist-boat transition states.  As this method builds on students’ understanding of the geometrical changes that occur in an S<sub>N</sub>2 reaction and carbonyl addition, it is easily adopted and applied.<br/>

A simple method for the visualization of chair and twist-boat transition states in torsionally controlled addition reactions

256th National Meeting (2018)

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