The Mechanism Substructure expression

• If the problem requires certain intermediate steps or intermediate compounds, this expression detects if they exist in the student’s response. It looks for the target compounds in any step or box of the student’s answer. (The starting materials and products are detected using the Mechanism Products and Starting Materials Is expression).
• Use this expression to evaluate specific mechanistic steps that the student may have incorrectly included or omitted. For example, you may want to look for a concerted carbonyl-enol tautomerization or a four-centered TS for proton transfer. When checking a specific mechanistic step, it's best to evaluate one step with one to three curved electron flow arrows at a time for effective expression triggering.
• Neither the substructure nor the response is aromatized. If the substructure contains an aromatic ring whose resonance structure is not degenerate, search for both resonance structures.
• Use the checkboxes if you want the evaluation to ignore charge, radical state, and/or isotope state in student responses.

The Compound Label is used for informational purposes only. It does not affect the evaluation, nor does it have to match the authored substructure or mechanistic step. The compound label field can hold up to 255 characters.

How to add a compound for comparison