Sanchez will be out of contract at the Emirates Stadium at the end of the season and Arsenal are understood to be willing to
cash in on the Chilean this month, even if it means losing him to a direct Premier League rival.
Manchester City have long been considered favourites to sign the 29-year-old and had an agreement in place last summer before Arsenal pulled the plug, but United have now emerged as frontrunners to beat their
local rivals to his signature.
Numerous reports on Twitter have claimed that the deal has now been finalised, with United offering Sanchez £350,000 a week in addition to a £30m transfer fee.
Arsenal boss Arsene Wenger revealed on Sunday that Sanchez's future could be decided within the next 48 hours, although official
confirmation has not yet arrived from either club.
Sanchez joined Arsenal in 2014 and has gone on to score 80 goals in 165 appearances for the club.