Portland is 11 hours behind Istanbul
There is no standard 8-to-6 overlap. Someone joins early or late.
For Istanbul and Portland, the standard workday in one city falls outside office hours in the other — that's what 11 hours of distance does. Keep live syncs short and infrequent, and let written updates carry the day-to-day between Istanbul and Portland. The window above shifts seasonally: Portland keeps daylight saving while Istanbul ignores it.