Arrow-Rotation-Method “ARM”, a Simple and Fast Method for Interconverting Fischer Projections and Zigzag Structures

Abstract

Different molecular representations are usually used to depict the three-dimensional (3D) structure of organic compounds. Mastering the skill of interconverting one form into another is essential for students to ensure success in organic chemistry. The traditional and recently developed methods for completing such interconversions that rely on 3D visualization of 2D paper (screen) structures, absolute configuration assignments, or multistep drawings that require 3D visualization are often time-consuming and difficult, especially for students with 3D visualization difficulties or a certain level of aphantasia, thus turning organic chemistry into a hurdle in their academic pathway. Given the importance of this topic and its impact on students’ understanding of organic chemistry, the Arrow-Rotation-Method (ARM) has been developed to interconvert zigzag structures and Fischer projections in a few simple steps that require only 2D visualization. A quantitative approach was used on a group of students enrolled in an introductory organic chemistry course to evaluate the time efficiency and usefulness of the new method. The results indicated that ARM significantly improved students’ performance in completing the various interconversions compared to the traditional methods and proved to be more student-friendly, time-efficient, and accurate, especially for compounds with multiple chiral centers. ARM was also successfully used to sketch the structure of complex compounds with multiple chiral centers upon conformational change.