torquoselectivity

https://doi.org/10.1351/goldbook.T06401
The preference for 'inward' or 'outward' rotation of substituents in @E01948-1@ or @E01948-2@ electrocyclic ring opening reactions.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1173 [Terms] [Paper]