Boris A. Berezovsky, once the richest and most powerful of the so-called oligarchs who dominated post-Soviet Russia, and a close ally of Boris N. Yeltsin who helped install Vladimir V. Putin as president but later exiled himself to London after a bitter falling out with the Kremlin, died Saturday.
Mr. Berezovsky was a Soviet mathematician who after the fall of Communism went into business and figured out how to skim profits off what was then Russian’s largest state-owned carmaker. Along with spectacular wealth, he accumulated enormous political influence, becoming a close ally of Mr. Yeltsin’s.
With Mr. Yeltsin’s political career fading, Mr. Berezovsky helped engineer the rise of Mr. Putin, an obscure former K.G.B. agent and onetime aide to the mayor of St. Petersburg who became president of Russia in 2000 and last May returned to the presidency for a third term.
After his election, Mr. Putin began a campaign of tax claims against a group of rich and powerful Russians, including Mr. Berezovsky and Mikhail B. Khodorkovsky, an oil tycoon, who remains jailed in Russia.
Mr. Berezovsky fled to London, where he eventually won political asylum and at one point raised tensions by calling for a coup against Mr. Putin.
