From what I could tell(didn't see it really good), a 3-pt shot was taken from the wing. Arthur Johnson(A2) was below the left block when the shot went up. McNeil(B2) from Syracuse was between A2 and the basket. As A2 started to move toward the basket B2 had his arm extended to locate A2 for a block out. As soon as A2 made contact with B2's arm A2 went sprawling to the floor. Lead who was on the opposite side of the lane immediately calls an intentional foul on B2.

Like I said I didn't see it very good but saw it well enough that it confused me as to why it was intentional.