DUBLIN—A senior Irish minister said on Tuesday he was confident the government would sign up to an overhaul of global corporate tax rules this week after updated proposals were circulated to negotiating countries. Ireland, the low-tax European headquarters for a number of the world’s largest multinationals, has declined to sign up to the Organisation for Economic Co-operation and Development (OECD) deal backed by all bar a handful of countries involved. Ireland chiefly opposed the introduction of a proposed minimum global rate of “at least” 15 percent, and in particular the phrase “at least” that it says would undermine the certainty its prized 12.5 percent rate has given companies for years. “I’m hopeful and confident that we will be able to be part of the solution here … I’m hopeful we will be able to sign up.” Environment Minister Eamon Ryan, who is also the leader of the junior coalition Green Party, …