B6 778 then B6 833 at Boston
Las Vegas → Boston → San Francisco
Timetable, Boston time
05:00B6 778 from Las Vegas at the gate
17:05B6 833 to San Francisco leaves the gate
12 h 05 apart on the timetable
B6 833 leaves 12 h 05 after B6 778 arrives on the timetable: more than half a day, so not a connection we count.