Disgraced Upper East Side gallery giant Lawrence Salander pleaded guilty yesterday to soaking John McEnroe, Robert De Niro and others in a $120 million art-fraud scheme.

In a deal first reported in The Post, the bankrupt Salander, 60, will be sentenced at a yet-chosen date to a yet-determined prison term — not to exceed a maximum of six to 18 years — based on how much restitution he manages to make.