LA 6139 then UA 877 at San Francisco
Boston → San Francisco → Hong Kong
Timetable, San Francisco time
23:58LA 6139 from Boston at the gate
23:15UA 877 to Hong Kong leaves the gate
23 h 17 apart on the timetable, overnight
UA 877 leaves 23 h 17 after LA 6139 arrives on the timetable: more than half a day, so not a connection we count.