Everyone attributes this to the antichrist my question is if he has destroyed the city and sanctuary how can he do scarifies and such for three and ahalf years into his perposed covenant?
The Scripture there is stating that after 69 "sevens", or 483 years, had passed, the Messiah (Jesus) would be "cut off", or crucified, and after that the people from whom the Antichrist will come would destroy Jerusalem and the temple.
The Antichrist is the one who puts and end to sacrifices three and a half years into the Tribulation. He does not destroy a city and a sanctuary; he will come from the same people who destroyed the city and the sanctuary in 70AD.