UA 3772 then UA 796 at San Francisco
Las Vegas → San Francisco → Boston
Timetable, San Francisco time
22:05UA 3772 from Las Vegas at the gate
21:30UA 796 to Boston leaves the gatealso VA 8308, NZ 9012
23 h 25 apart on the timetable, overnight
UA 796 leaves 23 h 25 after UA 3772 arrives on the timetable: more than half a day, so not a connection we count.