Opus Corp., formerly one of the country’s largest developers of commercial property, transferred tens of millions of dollars to its controlling family in the years preceding the collapse of the company’s operations. Now creditors of the closely held company are trying to get $150 million of that back from the company and the Rauenhorst family of Minnesota. A lawsuit filed earlier this year by a unit of the company on behalf of creditors charges that the parent company “siphoned” that money from the operating unit even though the subsidiary was technically insolvent.