Is it obligatory for a wealthy Muslim woman to donate from her money to the oppressed Muslims whose land the enemies are trying to occupy and kill them, such as in Palestine and other places?

It is obligatory for Muslims to assist their oppressed brethren through various means, including financial jihad, which is paired with jihad by one's self in the Holy Quran. This is an obligation upon the affluent, both men and women, especially when the enemy attacks, at which point there is no room for disagreement. Spending in the way of Allah is considered among the best forms of charity, and Allah multiplies its reward for whomever He wills.