The following are the M&A deals, rumors and chatter circulating on Wall Street for Wednesday December 5, 2012: Freeport-McMoRan to Acquire Plains Exploration and McMoRan Exploration in Deals Valued at $20B The Deal:Freeport-McMoRan Copper & Gold (NYSE: FCX ), Plains Exploration & Production Company (NYSE: PXP ) and McMoRan Exploration