By RAW an alchemist don't have a caster level, so he doesn't qualify for the requirements to take any crafting feats.
You can read more about it in this FAQ which states:
Is an alchemist a spellcaster for the purpose of crafting magic items other than potions?
As written, no, alchemists are not spellcasters, and therefore can't select feats such as Craft Wondrous Item.
The design team is aware that this creates some thematic problems with the idea of an alchemist creating golems and so on, and plan to examine this in the future.
That said, if you really want to craft magic items you could try to:
- Obtain a spell-like ability with a caster level high enought to qualify for the feat (usually the racial spell like have a caster level equal to your caracter level, so those are handy) or
- Take the master craftsman feat at level 5, and then the craft wonderous item (useless, since your wizard buddy already has it, probably 4 level sooner) or craft magic arms and armors