SAN FRANCISCO — It took less than 10 minutes Monday for a federal judge to kill the most controversial aspect of a proposed deal to end derivative claims over Hewlett-Packard Co.’s 2011 buyout of Autonomy.

U.S. District Judge Charles Breyer of the Northern District of California said under no circumstances would he approve an unconventional arrangement whereby plaintiffs lawyers would net $18 million plus sizable contingency fees by teaming up with HP in litigation against Autonomy executives.