alkene photocycloaddition

https://doi.org/10.1351/goldbook.AT07318
Photochemical process leading to formation of a cyclobutane upon addition of an @[email protected] alkene to another ground-state alkene or of an @[email protected] α,β-unsaturated carbonyl compound to a ground-state alkene. The latter is called a @[email protected].
Note:
A special case of @[email protected] is a @[email protected]
Source:
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 301 [Terms] [Paper]