While it's doubtful Toronto and New York would be willing to help Danny, this trade would make sense for all three teams:
BOS Gets: Willy Hernangomez, Norman Powell
TOR Gets: Jae Crowder, Kyle O'Quinn
NYK Get: Jakob Poetl, Marcus Smart, TOR 2018 1st, BOS 2018 1st
Boston gets a new big man and wing, and would have a rotation of:
Thomas/Powell
Bradley/Brown
Hayward/Tatum
Horford/MLE
Hernangomez/Zizic
With a starting five of Lowry, Derozan, Crowder, Valanciunas, and O'Quinn, this makes the Raptors better.
The Knicks gain two young pieces and two first round picks.
Who would say no?