The 14-year-old midfielder completed his move after spending four years at the Dons, during which time there he earned two England caps at Under-16 level.
"This is the opportunity of a lifetime for Seyi and his parents which has proved far too difficult to turn down," Dons chairman Peter Winkelman told the club's official website.
"There has been a lot of interest and speculation regarding Seyi which he has coped with admirably.
"We are extremely proud to have Seyi in our record books as our first schoolboy to receive an international cap.
"Everyone at the club would like to wish Seyi the best of luck in his future and we all look forward to the day he runs out at Anfield."
But Robinson was not in as generous mood, slamming the Premier League over the new Elite Player Performance Plan which reduces the amount of compensation big clubs have to pay for young talent.
“I went to watch our youth team this morning and I’m making a complaint,” he said. “It was a disgrace – I’ve seen something in this industry that I won’t accept. I want to make a point of it.
“There were three agents there going round trying to sign the kids of 14 and 15 years old. I’ve got them on tape and it will be done properly. Four Premier League clubs were there watching our players illegally. It’s a disgrace to our industry and I’m going right to the FA – right to the top. It made me sick.”