Do they have to be taught in schools to be considered classic? Most of the newer books that I consider classics would probably be considered inappropriate for teenagers by school boards. (Not by me, of course. Just by school boards.
Roberto Bolano - 2666, Savage Detectives
Don Delillo - White Noise, Underground
Philip Roth - The Human Stain, American Pastoral
Jonathan Franzen - The Corrections
Marilynne Robinson - Gilead
Out of those, The Human Stain is probably most likely to show up in schools.