If you want to avoid scary experimental features, the "classic" way to do this is by composition:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $rx_vowel = qr{ [aeiouAEIOU] }xms;
 my $rx_cons  = qr{ (?! $rx_vowel) [[:alpha:]] }xms;
 ;;
 my $rx_cvc = qr{ \b $rx_cons $rx_vowel $rx_cons \b }xms;
 ;;
 my $s = 'when did the cop get his cap and tape and run out too?';
 my @captures = $s =~ m{ $rx_cvc }xmsg;
 dd \@captures;
"
["did", "cop", "get", "his", "cap", "run"]
[download]

See perlre, perlretut, and perlrequick.

Update 1: Changed example string slightly to highlight difference between "cap" and "tape" (was "cape").

Update 2: Another ancient way to do this purely with character classes may be slightly faster because it avoids a lookaround:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $vowel = 'aeiouAEIOU';
 my $rx_vowel = qr{ [\Q$vowel\E] }xms;
 my $rx_cons  = qr{ [^[:^alpha:]\Q$vowel\E] }xms;
 ;;
 my $rx_cvc = qr{ \b $rx_cons $rx_vowel $rx_cons \b }xms;
 ;;
 my $s = 'when did the cop get his cap and tape and run out too?';
 my @captures = $s =~ m{ $rx_cvc }xmsg;
 dd \@captures;
"
["did", "cop", "get", "his", "cap", "run"]
[download]

Note, however, the tricky double-negative  [^[:^alpha:]\Q$vowel\E] in $rx_cons: "not not-an-alpha or a vowel". See "The POSIX character class syntax" in perlre.