Is a strong nucleophile a strong base?

Organic Chemistry: In base catalysed crossed aldol condensation, when two different aldehydes it is the less hindered lower aldehyde that acts as the nucleophile.Then when a ketone and an aldehyde condense why does the more hindered ketone act as the nucleophile?

• Answer:

  Successful crossed aldol reactions For this kind of crossed aldol reaction to work well we must have two conditions. • One partner only must be capable of enolization • The other partner must be incapable of enolization and be more electrophilic than the enolizable partner. Everyone remembers the first of these conditions, but it is easy to forget the second.