The alkene shown undergoes (i) $\mathrm{BH}{}_3$ in THF, then (ii) $\mathrm{H}{}_2\mathrm{O}{}_2$, $\mathrm{NaOH}$. Which structure is the major product? (Choose by relative configuration; one enantiomer of each racemate is drawn.)

The alkene is 1,2-dimethylcyclopentene. $\mathrm{BH}{}_3$ adds H and B to the same face, so the new H on one carbon and the new OH on the other are cis. The methyl group on the carbon that receives H is therefore on the face opposite to OH, which places the two methyl groups cis to each other: cis-1,2-dimethylcyclopentan-1-ol (racemic), the product of syn addition.