That’s what John Irving does. When he’s writing a novel, he writes the last sentence first. Then he writes the rest of the book toward that last sentence.
I’ve often heard writers say they write a first sentence and then follow that sentence. But Irving says he does the opposite. I think I may have done this once, for a short story. As a regular practice, though, I don’t think so. Not for me anyway.
What starts things for me is usually that first sentence, or a character, or an idea, or an image, or… something.
Irving discusses his approach in a video interview with The New York Times.