This is also useful for anyone going to IST.
TK is one of the most liberal as far as length of stopover, you can book your trip this way.
SCL-GRU-IST-ECN quick turnaround
ECN-IST
1 month later
IST-GRU-SCL
Priced out at $1600 at vayama.com, don't choose immediate turnaround at ECN (risk missing ECN-IST segment, thus the remaining ticket entirely) but opt for a few hours just to leave some margin.