Barcelona and Bayern among other admirers United hope they convince 15-year-old to stay Real Madrid are leading the race to sign the Manchester United teenager JJ Gabriel after he told the Premier League club he wants to cancel his registration . The 15-year-old has attracted interest from across Europe as his reputation has grown with academy performances. Barcelona have been keen to acquire him and Bayern Munich are known to admire the winger. It is understood Gabriel prefers a move to Europe…