While a recent U.S. intelligence report estimates that Russia’s oil-reliant economy is likely to suffer a slow decline over the next 18 years, several Am Law 100 firms are benefiting in the interim from a major reshuffling within the country’s natural resources sector, while also landing other assignments involving assets once owned by the Soviet state.

In the most notable of those transactions, Moscow-based Rosneft—75 percent of which is owned by the Russian government—continued its push to become one of the world’s largest oil producers by striking a deal this week to buy the half of TNK-BP it doesn’t already own from the so-called Alfa-Access-Renova consortium (AAR) of Russian oligarchs for $28 billion in cash. 

The agreement comes some two months after The Am Law Daily reported that Rosneft would buy the other half of TNK-BP, Russian’s third-largest oil company, from British energy giant BP for $17.1 billion in cash and a 12.84 percent stake in Rosneft. All told, the two deals value TNK-BP at roughly $56 billion, making Rosneft’s acquisition of the company the third-largest oil M&A deal in history and the largest ever in Russia.

As they have throughout Rosneft’s drive to take full control of TNK-BP, Cleary Gottlieb Steen & Hamilton and Skadden, Arps, Slate, Meagher & Flom took lead legal advisory roles on the deal announced this week. 

Cleary, which helped organize a Russia Day at the New York Stock Exchange last week, is fielding a team of lawyers on the current deal that includes M&A partners Russell Pollack and Daniel Braverman, antitrust partner Antoine Winckler, and finance partner Murat Akuyev. Also working on the matter is London-based corporate associate Gabriele Antonazzo, who will be promoted to the firm’s partnership on January 1.

Larisa Kalanda is deputy chair of Rosneft’s management board and serves as vice president of legal support for the company. Igor Maidannik is executive vice president of legal support at TNK-BP, where the chairman of the joint venture’s board is Igor Cheremikin, who also serves as chief legal officer at Russian conglomerate Renova.

Renova, which is controlled by Russian oligarch Viktor Vekselberg, is part of the AAR consortium. The group’s other members include Leonard Blavatnik‘s Access Industries and the Alfa Group, which is owned by fellow oligarchs Mikhail Fridman, German Khan, and Alexei Kuzmichov.

Skadden M&A partners Michal Berkner, Scott Simpson, Dmitri Kovalenko, and Linda Davies are leading a team from the firm advising both the Alfa Group individually and the AAR consortium as a whole. Other lawyers working on the matter include Skadden banking partner Mark Darley and counsel Andrew Brown, tax partner Tim Sanders, disputes partner David Kavanagh and counsel David Edwards, antitrust partner Ingrid Vandenborre, and corporate partner Clive Rough. (Offshore firm Conyers Dill & Pearman also advised the AAR consortium as a whole.)

Skadden successfully represented AAR last year in obtaining an injunction from a British high court barring BP from moving forward with a $16 billion joint venture deal with Rosneft designed to explore oil reserves off Russia’s vast Arctic coast. BP’s loss served as a double dose of good news for Skadden, which subsequently teamed up with Akin Gump Strauss Hauer & Feld to advise U.S. oil giant Exxon Mobil on its own $3.2 billion Arctic oil exploration deal with Rosneft last year. (That agreement came on the heels of a $1 billion Black Sea oil exploration deal struck by Rosneft and Exxon Mobil.)

As it happens, Akin corporate and tax partner Ilya Rybalkin in Moscow and corporate partner Steven Blakeley in London are advising longtime client Renova on the sale of its TNK-BP stake. Rybalkin joined Akin in 2010 from Hogan Lovells and took with him much of the firm’s work for Renova. Akin has handled several international arbitration proceedings for Renova related to management disputes regarding the joint venture, which has been beset by political tensions and even special forces raids since its creation back in 2003.

Weil, Gotshal & Manges senior private equity partner Marco Compagnoni in London is representing Access on the sale, as well as OGIP Ventures, a joint venture between Access and Renova formed to invest in TNK-BP. Also working on the deal for Weil are tax partner Brenda Coleman, corporate partner Peter King, and corporate associate Simon Lyell, who will be promoted to partner on January 1.

White & Case is advising TNK-BP on certain aspects of the company’s sale to Rosneft. The firm represented predecessor the Tyumen Oil Company and its AAR shareholders on their joint venture with BP forming TNK-BP back in 2003.

The TNK-BP sale, which is expected to close in the first half of 2013 pending the approval of Russian and European regulators, isn’t the only matter coming out of Russia of late that has pulled in Akin, Cleary, and Skadden.

Skadden’s Kovalenko and veteran European M&A partner Pierre Servan-Schreiber, who heads the firm’s Paris office, are advising automakers Renault and Nissan on their $742 million investment in an estimated $3 billion joint venture with state-backed conglomerate Russian Technologies. The deal is aimed at taking control of Russia’s largest carmaker, AvtoVaz, which is also one of the largest auto manufacturers in Eastern Europe.

Skadden, which previously advised suburban Paris-based Renault when it sold Swedish truck maker Volvo AB for $4.2 billion in 2010, also recently represented Russian billionaire Roman Abramovich and his investment firm Millhouse Capital on its roughly $1.5 billion acquisition of a nearly 6 percent stake in Moscow-based metal producer Norilsk Nickel.

As The Am Law Daily reported last week, that deal helped resolve an ongoing dispute between rival oligarchs Oleg Deripaska and Vladimir Potanin. In a separate matter, Skadden racked up nearly $60 million in legal fees representing Abramovich in litigation in the U.K. with exiled oligarch Boris Berezovsky.

Akin and Cleary are just two of several firms that have recently grabbed roles on a $1.7 billion initial public offering in London for MegaFon, Russia’s second-largest cell phone operator. While Cleary has taken the lead for MegaFon on the listing—the largest by a Russian company in two years, but one that has some investors seeing warning signs—Akin is advising MegaFon’s largest shareholder AF Telecom, which is controlled by yet another oligarch, Alisher Usmanov

Cleary is also advising privately owned Russian commercial bank Promsvyazbank on its plans for a $500 million IPO in London and Moscow, and the firm represented the country’s largest lender Sberbank in September on its $5 billion sale of a 7.6 percent stake held by the Russian government, according to our previous reports.

The spate of deals comes against the backdrop of Congress’s approval of the Sergei Magnitsky Rule of Law Accountability Act of 2012. The bill, which breezed through the U.S. House of Representatives by a 365-43 vote shortly before the Thanksgiving recess, is named after a former Russian lawyer at Moscow-based Firestone Duncan who died in jail at the age of 37 three years ago last month after allegedly running afoul of the country’s political elite. (The Am Law Daily reported in detail this summer about the challenges facing Russia’s legal system and the Magnitsky bill.)

The Magnitsky Act, which was tacked on to legislation normalizing trade relations with Russia, threatens sanctions for human rights abuses by members of Russian President Vladimir Putin’s regime. It is expected to be signed into law by President Barack Obama. The bill has been fiercely criticized by the Russian government and others for its perceived selectivity. Russia’s parliament responded last week by passing its own legislation targeting U.S. officials accused of human rights violations.

Putin, who has been pushing a patriotic platform since returning to the presidency earlier this year, faces tough options on how to face down the U.S. legislation, according to an op-ed published by The Moscow Times this week.

Meanwhile, in her ongoing quest to exact justice for her son’s death, Magnitsky’s mother filed a complaint against the Russian Federation in October with the European Court of Human Rights in Strasbourg, France. In late November, a Russian businessman who had provided evidence against the crime syndicate that led to Magnitsky’s incarceration was found dead near his mansion in the United Kingdom, making him the fourth person tied to the case to have died under mysterious circumstances.