Board Thread:Naruto Discussions/@comment-24593592-20140905144407/@comment-1018594-20140908003126

Kirsty Mikaelson wrote: Obito most likely told Sasuke of the plan off screen or in the manga off page, and how it worked etc.

I think Obito kept Sasuke in the dark about his true goals. As far as he knew, "Madara" would help him destroy the Leaf.