= Solution
\Image[/past-exam-of-the-chemistry-course-of-the-year-3-of-the-natural-sciences-course-of-the-university-of-cambridge/2022/paper-3-q39-ring-conformation.png]
{title=Preferred cyclohexene half-chair with the bulky tertiary-alcohol side chain pseudoequatorial}
Use a \b[<cyclohexene half-chair>], not a fully puckered saturated-cyclohexane chair. The <alkene> carbons and their directly attached bonds form the approximately planar end; the saturated part puckers. Put the $\mathrm{C(OH)(CH_3)_2}$ substituent pseudoequatorial at the opposite saturated methine to avoid a crowded pseudoaxial arrangement. Its methine proton is correspondingly pseudoaxial. This is a preferred <conformation>; the achiral spectra do not assign an absolute configuration.
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