UA 3851 then AC 744 at San Francisco
Rio De Janeiro → San Francisco → Toronto
Timetable, San Francisco time
17:41UA 3851 from Rio De Janeiro at the gate
16:40AC 744 to Toronto leaves the gatealso NZ 4501, NZ 4503, UA 8396
22 h 59 apart on the timetable, overnight
AC 744 leaves 22 h 59 after UA 3851 arrives on the timetable: more than half a day, so not a connection we count.