Boston College took a nine-point second-half lead, but the Tar Heels used a 19-3 run to retake the lead and advance in the tournament.
Donarski scored 20 points as the Tar Heels dispatched the Eagles to qualify for the conference's final eight for the third time in four seasons.
Percentages: FG 43.939, FT .611. 3-Point Goals: 9-22, .409 (Donarski 5-11, Crisp 2-3, Nivar 1-1, Grant 1-3, Townsend 0-2, Ustby 0-1, Hull 0-1) Turnovers: 15 (Gakdeng 3, Nivar 3, Donarski 2, Townsend 2, Grant 2, Ustby 1, Thomas 1, Crisp 1) Percentages: FG 43.333, FT .875.