use strict;
use warnings;
use Data::Dumper qw(Dumper);
$\="\n"; 

my @ext;
my @list=('f1.txt','f2.txtx','f3.xtxt','x1.txt');
my  $ex="f*.txt,f*.txt*";

print " Version 1: Not working--------------------------------";
@ext=map { $_=quotemeta($_).'$'; s/\\\*/.*/;} split(/,/,$ex);           # <<<<<< compare this line
print "qr=".Dumper(\@ext);
foreach my $e(@ext)
{ foreach my $f(@list) {print "Match: ($e) => $f" if ($f=~m/$e/); }}

print " Version 2: working--------------------------------";
@ext=map { my $x=quotemeta($_).'$'; $x=~s/\\\*/.*/g; $_=$x;} split(/,/,$ex);  # <<<<<< compare this line
print "qr=".Dumper(\@ext);
foreach my $e(@ext)
{ foreach my $f(@list) {print "Match: ($e) => $f" if ($f=~m/$e/); }}