It actually was a coup. Yanukovych was straddling Russia and the West. First and foremost he was looking out for his career. Taking the Western deal, with austerity, cuts in pensions, later retirement, etc. would have ended his poltical career. Russia gave him a better deal, so he took it.

The west wouldn't accept that, so they used the Nazis to ousted Yanukovych violiently.

His replacement was not elected, he was appointed. That is the definition of a coup.