use strict;
use warnings;

my $input = "<b></b>Officially called <>“event
+s,”</a> as "never events"";

print "input: $input\n";
$input =~ s/“/“/g; # change the lines
$input =~ s/”/”/gi;
$input =~ s/’/’/gi;
print "processed input: $input\n";
[download]

produces

input: <b></b>Officially called <>“events,&rdq
+uo;</a> as "never events"
processed input: <b></b>Officially called <>“e
+vents,”</a> as "never events"
[download]

This was done using your REs and appears to provide the output you are looking for.