According to UK media reports, Man Utd want to sign the 20-year-old who scored 17 goals and created the same number of assists last season as Dortmund finished second behind champions Bayern Munich.
Sancho is valued at around €120 million euros ($142 million) and Dortmund have said they have yet to receive an offer for their talented forward who joined in 2017 from Manchester City's academy.
"So far, there has been no contact between Borussia Dortmund and Manchester United in terms of Sancho," chief executive Watzke told Munich-based newspaper Sueddeutsche Zeitung.
"Not even indirectly or through so-called middlemen.There has never been an offer for Jadon, but there is a certain sum from us as to what should at least be paid," Watzke added, referring to the €120 million euros price tag.