Automated Timing for Video Subtitles
There is no professional tool that does this, as far as I know. It is never done, presumably because it would not be good enough and would need to be corrected by a human anyway.

There are of course many subtitling applications into which you can import your transcript and then do the spotting by hand. And they have varying features to make it easier/faster/more precise.

However, Youtube does offer automatic timing of transcripts. You may want to try it.

Using that, you could:


upload your video to youtube
upload your transcript
wait for their software to do the automatic timing
download the youtube captions 
... then probably still do manual corrections.