This was responsible for many DISCLOSURE rules and laws. A major change was that an assignee had to be named up front AND the profit disclosed. I cant remember if this is a Fed thing or just state by state. As an ex mortgage company operator, I remember my lenders wouldnt go for anything even close to that. A deal had to be 'seasoned' or it was ruled a flip. Though there is really nothing wrong with flipping a house for profit and the lenders should only be concerned with actual value vs their new loan, they all had cows over it and stopped short term ownership financing.
So, I do not know where Oregon stands on this but its impossible to answer the main question without knowing the exact details. One can interpret many ways the actual wording of the question. Elaborate and I can find out for you or call a real estate atty as someone else suggested.
If you are referring to selling your current residence and then closing the same day on a different property you are purchasing then it is more a question of coordination with all parties (buyers, sellers, lenders, escrow, etc.) than legality, as the other answers indicate.
However, if you are talking about purchasing a property and then simultaneously reselling that same property to someone at a profit that is a more complicated matter and one you might want to consult with a real estate attorney on.
While it happens regularly most agents and closing attorneys/company's don't recommend it as you've increased the risk of a crises exponentially. If the first closing gets delayed for any reason it can wreak utter havoc on the second closing. Agents understand why their sellers want it but you should think long and hard and have a serious conversation with all the parties involved in both transactions (specifically the lenders), before making a decision and if you do decide to do this, give everyone involved ample notice.