(Adds Starboard, Barington comments, background, shares)
May 22 (Reuters) - Starboard Value LP launched a fight to take over Darden Restaurants Inc's board, saying the planned sale of Darden's struggling Red Lobster chain was a "destructive transaction" that ignored the rights of shareholders.
Darden said last week it would sell the seafood chain to private equity firm Golden Gate Capital for $2.1 billion, defying Starboard and another activist investor Barington Capital.
Darden is under pressure from investors because of flagging sales at Red Lobster in the face of competition from cheaper chains such as Chipotle Mexican Grill Inc.
Darden reported a 1.1 percent fall in third-quarter revenue in March, with sales at established Red Lobster restaurants falling 8.8 percent.
The company rejected Starboard's push for a new board, saying the investor was seeking control of Darden despite owning only 6.2 percent. But Barington, which represents shareholders owning more than 2 percent of Darden, backed Starboard.
"It's time for a change in the Darden boardroom," Barington Chief Executive James Mitarotonda said in an email. "Darden desperately needs directors that will represent the interests of the owners of the company and not just the CEO and themselves."
Starboard, which said on Thursday that it had raised its stake in Darden from 5.5 percent, has been pushing Darden for a shareholder vote on the proposed sale.
Darden has said the deal is expected to close by August and is not subject to shareholder approval.
Starboard said it would nominate a full slate of 12 board candidates for election at Darden's annual meeting, the date of which has not been announced.
Nominees include Brad Blum, who Starboard said had turned around Olive Garden when he headed the chain between 1994 and 2002.
"By attempting to replace all 12 members of the board with its own preferred nominees, Starboard is seeking effective control of the company - representation which is disproportionate to Starboard's recently acquired ... stake," Darden said in a statement.
Starboard said it believed "wholesale board change is required to reverse the years of poor performance, poor governance and shareholder value destruction."
The investor also said it had identified ways to save costs and boost revenue.
A Darden spokesman said in an email that the board would consider the Starboard nominations "in due course."
Darden, which also operates the fast-growing LongHorn Steakhouse and Capital Grille restaurants, has said it will file a preliminary proxy statement this month for the requested meeting and convene it "as promptly as practicable."
In a letter to shareholders on Thursday, Starboard said that because of the tax-inefficient way the deal was structured, Darden would net only $100 million from the sale of Red Lobster after taking into account $1.5 billion it believed could have been realized from its alternative plan to sell the chain's real estate.
Darden's shares were up 2 percent at $49.68 in noon trading on the New York Stock Exchange. (Reporting by Arnab Sen, Aurindom Mukherjee and Maria Ajit Thomas in Bangalore; Editing by Ted Kerr and Kirti Pandey)