The Premier League side needed a deal-sheet extension to push through the season-long loan, and to send Jaidon Anthony in the opposite direction so Leeds would accept.
Anthony is a right-footed left winger. His is also a loan move.
The 23-year-old started in Arsenal's before joining the Cherries in 2016.
He made his Bournemouth debut in December 2020 against Preston North End in the Championship, establishing himself the following season with 45 appearances as Scott Parker’s side won promotion to the Premier League.
Anthony scored eight goals and provided six assists that season, and made 30 appearances in the Premier League last term.
He has started three of Bournemouth’s four matches this season.
He replaces Sinisterra, who refused to play in Leeds' matches against Birmingham City and West Bromwich Albion but made a goalscoring return at Ipswich Town after appearing to make peace with the fact Leeds would not allow him to leave.
Even when he spoke to the media at 1.30pm on deadline day, manager Daniel Farke declared himself "pretty confident" the Colombian would see out the year at Elland Road, but it has not proved to be the case.