Thank you for a very good question. The corporation of the boyars in 16th-17th century Russia did resemble the modern Russian ruling elite. The similarity was that the boyars had no individual power and constituted the backbone of the tsarist regime just as the oligarchs do in modern Russia. The difference was that the boyars had their own political tradition dating back centuries, and even the monarch had no right to violate it. Relations between the monarch and the elite were limited by rules of law and historical precedents. In modern Putin's Russia elites are very young, they have been formed last 30 years. The concept of law in these “new boyars” is completely absent. They all came out of the late Soviet Union, with its disrespect for law and private property, the power of bureaucracy, and nepotism.
Thus the boyar corporation and the oligarchy, similar in form, differ in their origins.