I want some clarification. Are you trying to create a hash with the keys of "A, B, C, D, E, and F", or are you trying to create a multi-dimensional datastructure, a hash of hashes of hashes of hashes (and so on)?

Here are a couple examples of "how to do it", depending on what it actually is:

# Create a hash with keys from @asdf
my %hash;
@hash{ @asdf } = (); # Use a hash slice.

# Create a multidimensional datastructure:
my $href;
foreach my $key ( reverse @asdf ) {
    $href = { $key => $href };
}
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The latter approach creates a datastructure referenced by $href. It's built "in reverse" just to simplify the algorithm.