Under contract before escrow closes on 1031 property - any tips ?

[Ron Masters]

To avoid a failed 1031 in his tight market (Los Angeles) I would like to go under contract with a replacement property before escrow closes on my property Im selling. 

Any clauses in the purchase contract to make it safer for me in case there is a hitch with my closing ? Example , backing out of the replacement property with no penalty in case that happens, Im looking for proper wording to put in the contract.

Im looking for feedback, is this a smart thing to do ? any problems with this scenario ?