If this deal fell on my lap, I would probably run from it.  It sounds to me like B is funding his purchase from A with the proceeds of the sale to C - classic land flip.  The only difference is that there is a private lender funding the A to B transaction, but the expectation is that it will be paid back almost immediately from the proceeds of the B to C transaction.  In my opinion, introducing a third-party into the transaction (you) doesn't change the substance of the transaction. 

Whether or not this can be legally structured, I cannot say. But, as a title agent, I wouldn't want any part of it. 

Best,
Robert A. Franco
SOURCE OF TITLE