my $startReplacement = qq~<table><tr><td>~;
my $endReplacement  = qq~</td></tr></table>~;
my $tag = 'quote';

1 while $string =~ s|
    \Q [ $tag ] \E  # oeffnender Tag gequoted
    (.*?)              # text gecaptured nach $1
    \Q [ /$tag ] \E # schliessender Tag gequoted
  |$startReplacement$1$endReplacement|gxis;