In 2009, the Seattle Seahawks sent the 37th overall choice to the Denver Broncos for a 2010 first-round pick. This trade worked out great for Seattle. Denver used the 37th pick for Alphonso Smith, who lasted one season with the team. The pick Seattle got from Denver wound up being 14th overall. The Seahawks used that choice to select Earl Thomas, who has become a Pro Bowl safety.
The Broncos made that trade with Seattle in part because they had an additional 2010 first-round choice acquired from Chicago in the Jay Cutler trade. The 49ers' division rival, St. Louis, has an additional first-rounder in 2014. I don't think the Rams will be trading that pick to San Francisco.