XPath 2.0: Find all descendants matching criteria X, but with no ancestor matching criteria Y

Given the xml:

<div itemtype="..." itemscope value="root">
  <div itemprop="..." value="1" /> <!-- want this -->
  <div value="2">
    <div itemprop="..." value="3" /> <!-- and this -->
  </div>
  <div itemtype="..." itemscope itemprop="..." value="4"> <!-- and even this -->
    <div itemprop value="5" /> <!-- but not this -->
    <div value="6" >
      <div itemprop value="7" > <!-- nor this -->
    </div>
  </div>
</div>

I am trying to build an xpath query that returns all descendants of the root, which have an itemprop attribute, but are not descendants of a "nested" element with the itemscope attribute. That is, I want all of the the root's properties, but not properties within nested scopes. I'm fairly convinced this cannot be done in XPath 1.0. My naive attempt: /descendant::*[not(@itemscope)]//*[@itemprop] returns all itemprop'ed elements that have some ancestor with no itemscope attribute