The Barcelona winger was tracked by the Red Devils this summer and considered as a top alternative to signing Borussia Dortmund attacker Jadon Sancho.
When it became clear they would not sign Sancho, United chiefs attempted to force through a loan deal for Dembele.
Dembele, 23, has struggled to reproduce his best form since a £117million transfer from Dortmund to the Camp Nou and Ronald Koeman wanted to offload him in order to make space for Lyon attacker Memphis Depay – who used to represent United.
Barcelona were happy to Dembele to leave this summer as long as he signed a new contract extension until 2023.
They were determined to protect themselves from risking losing him on the cheap as his contract would only have one year remaining once he remained on loan.
Dembele was uninterested in putting pen to paper on any such deal, but he was also firm in his stance to move to Old Trafford.
And according to Catalunya Radio, his desire to join Juventus was a major factor in his decision to turn down United.
He is already in talks with Juve over a move to Serie A next summer, while he could also run down his contract and leave on a free transfer in 2022.
So signing an extension to then move on loan to Manchester United was not an option for the France international, as he remains patient over his future move to the Italian giants.
They offered Douglas Costa as part of a potential deal – a proposal Barcelona turned down – while they asked about signing him later in the summer.
However, the deal didn’t come to fruition and he will have to remain patient over a move.