"CHARLES DICKENS, in a note now lying before me, alluding to an examination I once made of the mechanism of Barnaby Rudge, says—“By the way, are you aware that Godwin wrote his Caleb Williams backwards? He first involved his hero in a web of difficulties, forming the second volume, and then, for the first, cast about him for some mode of accounting for what had been done.”
I cannot think this the precise mode of procedure on the part of Godwin—and indeed what he himself acknowledges, is not altogether in accordance with Mr. Dickens’ idea—but the author of Caleb Williams was too good an artist not to perceive the advantage derivable from at least a somewhat similar process. Nothing is more clear than that every plot, worth the name, must be elaborated to its dénouement before anything be attempted with the pen. It is only with the dénouement constantly in view that we can give a plot its indispensable air of consequence, or causation, by making the incidents, and especially the tone at all points, tend to the development of the intention."
Basically what he's saying is you need to know the end before you start at the beginning, but beyond that it could be interesting to think about the ending first. In other words, you think about what is the worst kind of situation you could put your character into and then work backwards. I'm not sure how practical it is for working out a whole story, but it certainly could be a great brainstorming method.
It will probably work best once you know your protagonist well. For instance, I'm just starting to work on a plot in which the protagonist is a very rational (in fact, a bit too rational) character. If I decide I want him to end up in jail, his personality would guide me to the most likely events that could lead to that. In his case, it wouldn't be that he gets drunk and into a fight, but it might be that he sees someone violating some minor law (like littering) and tries to enforce it himself and that could escalate into a conflict that gets him arrested.
(There's more advice on plotting and characterization in my book, "Your Writing Coach," available from Amazon and other online and offline retailers. Also see the related site, www.yourwritingcoach.com)