Reuven wants to lend Shimmon money backed by a piece of real estate that belongs to Shimmon. Instead of lending money, they make a deal that Reuven will purchase the real estate for the amount of money and as part of the deal Shimmon has an option to buy back the real estate at a later time for a pre-determined price which is higher than the original amount.
So, for example, Reuven purchases it for $10,000 and Shimmon has a contractual option to buy it back at $12,000 a year later.
Are there any Ribbis implications in this contemplated transaction, and if so what?