Desynthesis has been implemented.
Players can acquire the desynthesis skill by completing the following quest:

Quest Gone to Pieces
Required Level Disciple of the Hand level 30
Location Ul'dah - Steps of Thal (X:14 Y:10)
NPC: Syntgoht
Prerequisites Players must first complete the main scenario quest "Life, Materia, and Everything."

Source: Patch notes is your friend.

http://na.finalfantasyxiv.com/lodest...582d59335acd84