Take a look at Regexp::List. Consider:

use strict;
use warnings;
use Regexp::List;

my @words = qw!bob fred frederic ann anne annie!;
my $target = <<DATA;
This list contains Bob, Frederic, Fred, Robert, Annette and Ann.
And this list conatins Fred and Frederic.
DATA

my $match = Regexp::List->new (modifiers => 'i')->list2re (@words);
my @matches = $target =~ /($match)/g;

print "@matches";
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Prints:

Bob Frederic Fred Anne Ann Fred Frederic
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