When is it better to draw Sawhorse projections in comparison with other projections?
Sawhorse projections generally show when something is antiperiplanar or synperiplanar, more easily than something like a Newman projection or a basic line structure can.
Take ethane as an example.
An antiperiplanar conformation has a
A synperiplanar conformation has a
A sawhorse projection approximates this 3D structure extremely well, and allows one to judge whether an
A Newman projection would depict the dihedral angle correctly, but because one would be viewing the important atoms from the front instead of an aerial view, you might actually be looking at an octahedral molecule (with a main-chain bond length of