Chapter 2 o In a chair flip, the axial will go to the equatorial position and vice versa. o You want the largest group(s) to be in the equatorial position. Cis/Trans Isomerism Cis Isomers: the groups are on the same face or The two structures on the right are equivalent. Trans Isomers: the groups are on opposite faces or The two structures on the right are not the same because the methyl groups are on opposite faces. Drawing Chair Conformations o up (∧) and forward  axial o up (∧) and behind  equatorial o down (∨) and forward  equatorial o down (∨) and behind  axial o example #1: methyl cyclohexane and Drawing Chair Flips with Two Substituents o example #1: cis – 1, 2 – dimethyl cyclohexane Both chair conformations contain one axial and one equatorial methyl group. o example #2: trans – 1, 2 – dimethyl cyclohexane The first chair conformation contains two axial methyl groups, while the second chair conformation contains two equatorial methyl groups – making the second one more stable. o example #3: cis – 1, 3 – dimethyl cyclohexane The first chair conformation contains two axial methyl groups, while the second chair conformation contains two equatorial methyl groups – making the second one more stable. o example #4: trans – 1, 3 – dimethyl cyclohexane Both chair conformations contain one axial and one equatorial methyl group.