I think you're thinking of the Pasadika Sutta, DN 29.
It does not actually say that the Jhanas lead to the 4 fruits. Rather, it says addiction to the pleasures of the Jhanas (sukhallikānuyoge anuyutta) leads to the 4 fruits.
You can see a contrast of this in the First Sermon, where the Buddha put down kāmesu kāmasukhallikānuyogo (sensual addiction) as an extreme to be avoided by a monastic. This mirrors the passage in DN 29, where one of the 4 sukhallikānuyoga that is criticised is the case of a person throwing himself into indulgence in the 5 cords of sensual pleasure/desire (pañcahi kāmaguṇehi samappito samaṅgībhūto paricāreti).