Torquoselectivity

{
  "id": "MLC-T-CHM-012122",
  "term": "Torquoselectivity",
  "field": "Chemistry",
  "definition": "The tendency of a substituent to turn inward or outward when a ring opens or closes by a conrotatory or disrotatory electrocyclic process. Orbital symmetry fixes the rotation mode but not which of the two allowed directions each substituent takes; that is decided by steric and electronic effects, with donor groups tending to rotate outward and acceptor groups inward. The ring opening of 3-substituted cyclobutenes is the standard case.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "electrocyclic reaction"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1173 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/torquoselectivity/"
}