Before Edo Itachi went off to face Kabuto he told Naruto that he trusted him to take care of Sasuke:
Itachi acted like the evil older brother to deceive Sasuke, as a part of this persona he always told Sasuke to kill his best friend and come before him with the mangekyou.
One may argue that Itachi would not have known that Naruto was Sasuke's best freind, or would become Sasuke's best friend. However, Itachi finds out Naruto's determination to protect Sasuke before his battle with Sasuke:
Even after this he criticizes Sasuke for not having the mangekyou:
I know that Itachi was again putting on an act here, but how did he know that Sasuke wasn't going to to kill Naruto? So he trusts Naruto with saving Sasuke, but always told Sasuke to kill naruto. Hypocrite much?