The global reordering of the auto industry took a big step forward on Friday as an unlikely alliance led by Magna International, a Canadian auto parts maker, and Sberbank of Russia tentatively agreed to buy the European operations of General Motors.

The deal was brokered by the German government in Berlin, with negotiations stretching from Moscow to Washington, Detroit, Ontario and New York, where G.M.’s board gathered for a meeting ahead of an expected bankruptcy filing on Monday.

With sales plunging to levels not seen in decades, auto companies are seeking refuge in mergers or bankruptcy court. Other companies, like Magna and Fiat, are seeing opportunities in beaten-down automakers, hoping to buy them or form alliances on the cheap.

The deal in Germany will have ripple effects in the United States.

Fiat had hoped to grow into a top-tier global company virtually overnight, with its nearly completed alliance with Chrysler and by buying G.M. of Europe, which includes Opel of Germany as well as the British auto company Vauxhall.