I don't think so.
Do they need it, anyways? They already have a discovery that functions like extend spell, but let's look at the rest. Silent spell wouldn't do anything, Still spell would be silly, Widen spell wouldn't work for a single one of the extracts, neither would enlarge spell, I think, and Heighten Spell seems really pointless. That leaves Empower Spell, Maximize Spell, and Quicken Spell. Empower Spell and Maximize seem to only function for a select few spells like the cure spells and a few ones like Aid (although a discovery that empowered cure spells sounds kickass). Quicken Spell might work, I guess, but you'd get off a 2nd level extract at maximum.
I don't think metamagic for Alchemists would benefit them at all.
|Kamai Star Voter 2013, Star Voter 2014|
Well, being able to use metamagic opens up metamagic rods, which could be a real option at high levels.
Again, what would the metamagic rods do? You could get extend (since the alchemist ability only works on potions, not infusions), Empower, and Maximize that would at all help. All of them, even in rods, are of limited use, and by just blanket allowing metamagic feats, interactions with non-core feats might become wonky. Now that I think about it though, something like rapid spell could make for an interesting discovery (1 minute to make infusion to 1 full round action).