A key community panel on Monday rejected plans for a casino next to the United Nations, marking the third casino proposal to fail in Manhattan and ensuring no casino will be green-lit in the borough in the immediate future. The rejection of the Freedom Plaza proposal, by a 4-2 vote, came despite last-minute sweeteners by the developers, who promised to augment the sprawling development with nearly 1,100 units of affordable housing. As with those votes, the only committee members who voiced support for the Freedom Plaza application were appointees of Gov. The $11 billion Freedom Plaza project, located along the East River, was jointly developed by Soloviev Group and Mohegan. “For this reason, we support the CAC’s decision today to not advance the casino proposal at Freedom Plaza.”This article was updated with additional comment.