Either way, the plumber who piped the basement work fucked you a little bit, he didn't leave enough space between the cleanout and 3x2 wye for you to be able to work with. I'm a licensed union plumber in Boston, and if I was doing this on the side I'd buy a 4x1 1/2 TY and cut it in to the 4 inch. I'd cut the exact make in of that fitting and then see if you had vertical play in that stack to glue it right in, if not I'd buy a 4'' pvc slip coupling to make that work. I'd pipe it right over to the sink and not worry about a vent. With the 3" draining in to the 4" I wouldn't worry about siphonage from that vertical momentum and the arm off that 4X1 1/2 TY is short enough that I wouldn't worry about the drain being choked off by the hydraulic gradient of the drain.