The Whites have so far failed to make an appointment to replace Jesse Marsch, who was sacked as boss earlier this month.
Leeds have approached several managers and zeroed in on Feyenoord’s Slot as someone they wanted to take charge at Elland Road.
They approached Feyenoord and Slot, but the Dutchman turned down their advances as he wanted to stay at De Kuip.
And according to Dutch daily De Telegraaf, Leeds were prepared to pay compensation of €3m in order to take Slot to the Premier League.
Leeds have also pursued Rayo Vallecano boss Andoni Iraola, but the Spanish side are against losing him.
And the Rayo Vallecano manager is reluctant to force his way out by using the release clause in his deal.
Currently, Under-21s boss Michael Skubala is leading a caretaker team at Elland Road and preparing the Whites for their next match.
