The 16-year-old midfielder confirmed the move via his Instagram account.
Sanchez and Ozil can leave Arsenal on a free if they don't agree extension by next summer.
Dembele moved to Barcelona from Dortmund for a club-record fee of €105m.
Rooney also gave his thoughts on Jose Mourinho and Louis van Gaal.
Wenger signed a new two-year deal at Arsenal after helping his side win the FA Cup in May.
Pereira will spend the 2017/18 campaign with La Liga outfit Valencia.
Bielik impressed during pre-season and was expected to go out on loan this summer.
Coleen had reportedly cut a holiday short after her husband was charged with drink-driving.
Sporting's Nuno Saraiva called Sullivan a 'liar' for his comments regarding West Ham's pursuit of William Carvalho.
Liverpool held firm over Coutinho and Klopp is happy with the situation the club is facing.
Former midfielder Paul Merson thinks Drinkwater would at least show commitment.
Wenger also revealed that the Gunners will attempt to sign Lemar again.
Sanchez, 28, came close to joining Manchester City on deadline day.
Coutinho's desired move to Barcelona failed to materialise.
Gunners have lost two of their opening three fixtures in the Premier League this season.
Lukaku has scored three goals in three league games so far.
Director Albert Soler claims Argentine will formally sign new deal agreement soon.
Spanish midfielder will not return to top-flight action until at least January after undergoing eight operations.
Injured playmaker breaks silence on what really transpired at the 11th hour on transfer deadline day.
Director Albert Soler says Catalan giants were not prepared to engage in such an inflated market.
Ibrahimovic was re-signed by United after he was released earlier in the summer.
Sullivan also lifted the lid on some late deadline day drama involving a club-record pursuit of William Carvalho.
Former Real Betis starlet suffered a real injury scare during Friday night's Under-21 clash between Spain and Italy.
Costa is on a self-imposed exile in his hometown in Brazil and is not keen on returning to Chelsea.
Laura Simpson was with the footballer when he was arrested for drink-driving after a wild night in Cheshire.
Remy has signed a two-year deal with the Spanish side.
Munir spent the last season on loan at Valencia and scored six goals in the process.
Dolberg was extensively scouted by United last season.
Sanchez was close to completing a deadline day move to Manchester City.
Pereira, who spent the last season on loan at Granada, has joined Valencia on loan.