Ambidentate Enolate Ions 2
According to Pearsons hard soft [Lewis] acid base principle, hard Lewis acids have a strong affinity for hard Lewis bases and soft Lewis acids have a strong affinity for soft Lewis bases.

Enolate ions have a hard alkoxide ion end which preferentially displaces alkyl-Nfg(hard) complexes, such as oxonium ions, and a soft nucleophilic carbanion end displaces soft nucleofuges (such as iodide ion) from alkyl-Nfg(soft) complexes.

Note that while hard vs soft comparisons can be made for carefully selected pairs of species and/or reactive centres, the HSAB analysis is NOT general. For more information look in the Chemogenesis webbook section on Pearson's HSAB principle.