The Dukes (21-14) advance to meet top-seeded Indiana (27-6) on Friday night.
James Madison was without suspended starter Rayshawn Goins for the first half but built a big lead.
Goins, who leads James Madison in scoring (12.7) and rebounding (7.4), was suspended for the first half following a weekend arrest.
Police in Harrisonburg, Va., said they were called to break up a party early Sunday morning and Goins was shouting obscenities at them.
He was not arrested on site, according to the police, for fear the crowd would “turn riotous.”
Goins came in early in the second half and finished with four points in 13 minutes.
LA SALLE 80, BOISE STATE 71
Tyrone Garland led La Salle’s guard-driven offense with 22 points, and the Explorers (22-9) wrapped up the NCAA Tournament’s First Four by beating Boise State (21-11).
The 13th-seeded Explorers play fourth-seeded Kansas State on Friday.
SYRACUSE: The school has been under investigation for possible NCAA violations, mostly in its basketball program, for at least a year, according to two media reports.
CBS Sports.com, citing an unidentified source, reported Wednesday that the school has received a letter of preliminary inquiry from the NCAA.
The Post-Standard in Syracuse reported NCAA investigators have been conducting interviews with Syracuse employees and former employees. The newspaper said the investigation includes the handling of former player Fab Melo’s academic eligibility.
“Same story they had last year at this time,” coach Jim Boeheim said.