The Destruction of Praxis took place in 2259 of the Kelvin timeline.
Prelude[]
For centuries, Praxis served as the key-energy production for both the Klingon Empire and Qo'noS. It supplied them with pergium, topaline, and uranium. Following the Destruction of Vulcan, Starfleet's Admiral Marcus and Section 31 foresaw a war with the Klingon empire. Thus they started to search for ways to defend the Federation. One of their ships discovered the SS Botany Bay. There they found Khan Noonien Singh and 72 of his fellow augments. Section 31 then had Khan surgically altered, his memory erased, and was given a new identity as Commander John Harrison. During this time, Starfleet and Section 31 attempted to damage Praxis, to no avail. (ST reference: Federation: The First 150 Years; TOS - Khan comic: "Issue 4")
The destruction[]
Khan then devise a way to utterly destroy Praxis by using portable beaming device to infiltrate Praxis. There, he was able to subdue and kill the Klingons stationed there. (TOS - Khan comic: "Issue 4")