Istanbul is 11 hours ahead of Portland
There is no standard 8-to-6 overlap. Someone joins early or late.
For Portland and Istanbul, 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 Portland and Istanbul. The window above shifts seasonally: Portland keeps daylight saving while Istanbul ignores it.