SAN FRANCISCO — One of ailing Dewey & LeBoeuf‘s most valued assets is moving to Weil, Gotshal & Manges, ending months of speculation.

Rainmaker Richard Climan has joined Weil’s M&A group in Silicon Valley, along with a high-profile team that includes partners Keith Flaum, Jane Ross and James Griffin. Dewey partner John Brockland is joining Weil’s technology and IP transactions group.

Climan said the team was courted by dozens of firms, but had serious discussions with only about four or five, which he declined to name. And they did not seek compensation guarantees from any of them, he said.

The solid reputation of Weil’s attorneys and the firm’s collaborative culture were a big draw. But its global reach was perhaps the deciding factor for the team, Climan said. While the team will be based in Silicon Valley, its practice is focused on handling international deals.

“We know their practices and know the reputation of Weil’s practitioners and how good they are,” Climan said in an interview. “And we needed a firm that could accommodate very easily a high-end M&A practice. But we needed a firm that could do it globally.”

Climan said the group going to Weil comprised about a dozen people, including four associates. Recruiters say the additions are a big coup for Weil, whose Silicon Valley presence took a hit in June 2011 when star patent litigator Matthew Powers left to start his own plaintiffs firm.

“Weil has steadily been developing a very strong private equity practice, and they have long wanted an M&A group with deep expertise handling large and sophisticated deals,” said Natasha Innocenti, head of Major, Lindsey & Africa’s partner practice in Silicon Valley. “And this group is exactly that.”

All five attorneys have worked together for nearly 15 years.

Climan, Flaum and Ross rocked Silicon Valley in 2009 after announcing that they, along with tech practice leader Eric Reifschneider, were leaving Cooley, their long time home, for Dewey’s small East Palo Alto office. The Recorder reported at the time that Dewey had agreed to pay Climan a multiyear guarantee of $3.5 million annually. Ross, Brockland and Reifschneider, who left Dewey to join Qualcomm Inc.’s tech licensing division in March, reportedly got $1.5 million each. Many have pointed to Dewey’s practice of awarding large compensation guarantees as a big factor in its recent financial woes.

Since then, the team has handled big deals in both the tech and life sciences industry for clients such as Adobe Systems Inc., Applied Materials Inc., Dell Inc., eBay Inc., Gilead Sciences Inc., Oracle Corp., Synopsys Inc. and Zynga Inc.

Earlier this year, Climan headed the legal team that successfully defended Illumina Inc. against a $6 billion takeover bid by Roche Holding. Climan was also the lead M&A lawyer for the Los Angeles Dodgers in its $2 billion acquisition by a consortium that included basketball star Earvin “Magic” Johnson.

“We’ve known these guys for quite some time, both personally and professionally,” said Craig Adas, managing partner of Weil’s Silicon Valley office. “We view this as an extremely low-risk addition. They are the pre-eminent tech M&A practice in the U.S., and that’s incredibly attractive to us and is perfect for our office.”

And Climan said the popular monthly M&A forums that he hosts in Silicon Valley will continue, at a location to be determined. “I’m not sure where, but the show will go on,” he said.